Inclusion Criteria:

• Individuals 35-50 years of age, inclusive
• Patients who are undergoing risk-reducing salpingo-oophorectomy (RRSO) (for the BSO arm) and patients who have declined or elected to defer BSO after proper counselling to clearly explain the standard of care for BRCA1 mutation carriers and are undergoing salpingectomy (for the BLS arm with delayed oophorectomy arm). Concurrently planned hysterectomy with either arm is permitted
• At least one intact ovary and fallopian tube is in situ at the time of counseling and consent. Prior hysterectomy is allowed provided it did not include bilateral salpingectomy. Prior tubal ligation is allowed if one intact ovary and fallopian tube (with fimbria not removed) are present
• Positive Clinical Laboratory Improvement Act (CLIA)-approved test results for pathogenic or likely pathogenic germline BRCA1 mutation in the patient. Documentation of the result is required
• Patients may be premenopausal or menopausal
• Transvaginal ultrasound (TVUS) and CA-125 within 180 days of registration
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry
• Individuals who are currently pregnant or plan to become pregnant in the future through assisted reproductive technologies and who have received proper counseling are eligible. Individuals who are currently pregnant and plan bilateral salpingectomy at the time of a planned cesarean section are eligible. Patients must understand that they will not be able to become pregnant naturally in the future

Exclusion Criteria:

• Individuals with a history of any prior cancer who have received chemotherapy within the past 30 days or radiotherapy to abdomen or pelvis at any prior time
• Prior history of ovarian cancer, including low malignant potential neoplasms (LMP), primary peritoneal carcinoma, or fallopian tube carcinoma
• Patients medically unfit for the planned surgical procedure
• Patients with abnormal screening tests (TVUS, CA-125) suspicious for occult or gross pelvic malignancy or neoplasm within the past 180 days
• An abnormal TVUS is defined as morphologic or structural variations suspicious for ovarian malignancy or complex cystic lesions (simple cysts < 5 cm in maximal diameter are not exclusionary)
• An abnormal CA-125 is defined as a level > 50 U/ml in premenopausal individuals if they are not current users of oral contraceptives; an abnormal CA-125 is defined as a level > 40 U/ml for premenopausal individuals who are current users of oral contraceptives. An abnormal CA-125 is defined as a level > 35 U/ml in postmenopausal individuals.

Key Inclusion Criteria:

1. Female and at least 18 years old. 2. Histologically or cytologically confirmed recurrent high grade epithelial ovarian, primary peritoneal, or fallopian tube cancer with histologic subtypes of serous, clear cell or endometrial for which there is no known or established treatment available with curative intent. 3. Have demonstrated relapse within 6 months of platinum therapy (platinum-free interval <6 months). 4. Must have evaluable or measurable disease according to RECIST v1.1 criterion: defined as at least one lesion that can be accurately measured. 5. Adequate hematologic and organ function. 6. Ability and willingness to take oral medication. 7. If unknown homologous recombination deficiency (HRD) status, subjects must provide formalin-fixed, paraffin-embedded tumor samples available from the primary or recurrent cancer or agree to undergo fresh biopsy prior to study treatment initiation. 8. Willingness to release archival tissue for research purposes or to undergo a tumor tissue biopsy prior to dosing on Cycle 1 Day 1.

Additional Key Inclusion Criteria for Phase II:

9. This supersedes inclusion criterion 3 (above). Demonstrated relapse within 6 months of platinum therapy, while taking a PARPi as maintenance: a minimum of 3 months is required if the participant received PARPi maintenance following first-line chemotherapy. 10. Must have measurable disease according to RECIST V1.1 criterion: defined as at least one lesion that can be accurately measured.

Key Exclusion Criteria:

1. Prior therapy directed at the malignant tumor within the last four weeks prior to Cycle 1 Day 1 (6 weeks for nitrosoureas or mitomycin C). 2. A minimum of 10 days between termination of the prior PARPi and administration of ZN-c3 and niraparib treatment is required. 3. Any investigational drug therapy <28 days. 4. Prior treatment with a WEE1 inhibitor. 5. Known hypersensitivity to any drugs similar to ZN-c3 and/or niraparib in class or its excipients. 6. Participant has any known history or current diagnosis of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). 7. Uncontrolled hypertension (Diastolic BP > 90 mmHg or Systolic BP > 140 mmHg). 8. Myocardial impairment of any cause (e.g., cardiomyopathy, ischemic heart disease, significant valvular dysfunction, hypertensive heart disease, and congestive heart failure) resulting in heart failure by New York Heart Association Criteria (Class III or IV). 9. Significant gastrointestinal abnormalities, requirement for IV alimentation, active peptic ulcer, chronic diarrhea, or vomiting considered to be clinically significant in the judgment of the Investigator, or prior surgical procedures affecting absorption. 10. 12-lead ECG demonstrating a corrected QT interval using Fridericia's formula (QTcF) of >480 ms, except for subjects with atrioventricular pacemakers or other conditions (e.g., right bundle branch block) that render the QT measurement invalid. 11. History or current evidence of congenital or family history of long QT syndrome or Torsades de Pointes (TdP). 12. Taking medications with a known risk of TdP (according to current information provided at https://crediblemeds.org).

Inclusion Criteria:

• There is no age limit for the low risk stratum (stage I ovarian immature teratoma and stage I non-seminoma or seminoma malignant GCT [all sites])
• Standard risk 1: Patient must be < 11 years of age at enrollment
• Standard risk 2: Patients must be >= 11 and < 25 years of age at enrollment
• Patients enrolling on one of the low risk arms must be newly diagnosed with a stage I germ cell tumor; for the standard risk arms, patients must be newly diagnosed with metastatic germ cell tumor (stage II or higher); histologic confirmation of a primary extracranial germ cell tumor in any of the categories outlined below is required of all patients at enrollment except for those who were initially diagnosed with stage I non-seminoma malignant GCT and later recur during observation post surgery off study; for these patients, if elevated tumor markers rise to > 5 x upper limit of normal (ULN) on at least 2 measurements taken at least 1 week apart, a diagnostic biopsy is not required for enrollment
• Low risk stage I immature teratoma (IT); site: ovarian; stage: Children's Oncology Group (COG) stage I, Federation of Gynecology and Obstetrics (FIGO) stage IA and IB; grade: 2 or 3; histology: pure immature teratoma (may contain microscopic foci of yolk sac tumor), mixed immature and mature teratoma, (no pathological evidence of MGCT); tumor markers: alpha-FP =< 1,000 ng/mL, beta-HCG institutional normal; all ages
• Low risk stage I non-seminoma MGCT; site: ovarian, testicular, or extragonadal; stage: COG stage I, FIGO stage IA and IB, American Joint Committee on Cancer (AJCC) testicular stage IA, IB and IS; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma (pure or mixed); all ages
• Low risk stage I seminoma-MGCT; site: testicular; stage: COG stage I; AJCC testicular stage IA IB, and IS; histology: must contain at least one of the following: may contain immature/mature teratoma; may NOT contain yolk sac tumor, embryonal carcinoma, or choriocarcinoma; all ages
• Standard risk 1 (SR1); site: ovarian, testicular, or extragonadal; stage: COG stage II-IV, FIGO stage IC, FIGO stage II-IV (International Germ Cell Consensus Classification [IGCCC] criteria DO NOT apply); histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) < 11
• Standard risk 2 (SR2)
• Site: ovarian; stage: COG stage II and III, FIGO stage IC, II and III; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Site: testicular; stage: COG stage II-IV, AJCC stage II, III, IGCCC good risk; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; tumor markers: must be IGCCC good risk; post op: alpha-FP < 1,000 ng/mL, beta-HCG < 5,000 IU/mL and lactate dehydrogenase (LDH) < 3.0 x normal; age (years) >= 11 and < 25
• Site: extragonadal; stage: COG stage II; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Notes:
• IGCCC criteria only apply to SR2 patients with a testicular primary tumor
• Use post-op tumor marker levels to determine IGCCC risk group
• Stage 1 seminoma patients are not eligible for the standard risk arms of the study
• For the low risk stage I non-seminoma MGCT and the standard risk arms, components of yolk sac tumor, embryonal carcinoma, or choriocarcinoma can be mixed with other forms of GCT, such as seminoma or mature or immature teratoma; if yolk sac tumor is the only malignant component present, then it must be deemed by the pathologist to be greater than a "microscopic component" of yolk sac tumor
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, 2 or 3; use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Organ function requirements apply ONLY to patients who will receive chemotherapy (SR1 and SR2 patients)
• Adequate renal function defined as:
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 (within 7 days prior to enrollment) OR
• A serum creatinine based on age/gender as follows (within 7 days prior to enrollment): (mg/dL)
• 1 month to < 6 months male: 0.4 female: 0.4
• 6 months to < 1 year male: 0.5 female: 0.5
• 1 to < 2 years male: 0.6 female: 0.6
• 2 to < 6 years male: 0.8 female: 0.8
• 6 to < 10 years male: 1 female: 1
• 10 to < 13 years male: 1.2 female: 1.2
• 13 to < 16 years: male: 1.5 female: 1.4
• >= 16 years male: 1.7 female: 1.4
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment)
• Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) or serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) < 2.5 x upper limit of normal (ULN) for age (for the purpose of this study, the ULN for SGPT is 45 U/L) (within 7 days prior to enrollment)
• Peripheral absolute neutrophil count (ANC) >= 1,000/mm^3 (within 7 days prior to enrollment) AND
• Platelet count >= 100,000/mm^3 (within 7 days prior to enrollment)
• Patients enrolling on the standard risk arms must be medically fit to receive protocol treatment and with no contraindications to protocol treatment
• Eligibility criteria to participate in the pilot study of the AYA-Hears instrument (patient reported outcomes [PROs] of ototoxicity) Note: participants in group 1 will not receive AGCT1531 protocol-directed therapy; all other AYA-HEARS patients must be enrolled on the AGCT1531 SR2 arm in order to participate
• >= 11 and < 25 years old at enrollment
• Able to fluently speak and read English
• Has received prior cisplatin- or carboplatin-based chemotherapy regimen for malignancy including diagnoses other than germ cell tumor
• Followed for cancer or survivorship care at one of the following institutions:
• Baylor College of Medicine/Dan L Duncan Comprehensive Cancer Center
• Dana Farber/Harvard Cancer Center
• Hospital for Sick Children
• Children's Hospital of Eastern Ontario
• Oregon Health and Science University
• Seattle Children's Hospital
• Yale University

Exclusion Criteria:

• Patients with any diagnoses not listed including:
• Stage I testicular cancer patients who have undergone primary RPLND (retroperitoneal lymph node dissection)
• Pure dysgerminoma
• Pure mature teratoma
• Pure immature teratoma COG stage I, grade I
• Pure immature teratoma COG stage I, grade 2,3 with alpha-fetoprotein (AFP) >= 1000 ng/mL
• Pure immature teratoma COG stage II - IV or FIGO stage IC to IV
• "Poor risk" GCT (age >= 11 years old and COG stage IV ovarian, COG stage III or IV EG, or IGCCC intermediate or poor risk testicular), or
• Primary central nervous system (CNS) germ cell tumor
• Germ cell tumor with somatic malignant transformation
• Spermatocytic seminoma
• Patients must have had no prior systemic therapy for the current cancer diagnosis
• Patients must have had no prior radiation therapy with the exception of CNS irradiation of brain metastases; (this exception only applies to SR1 patients; any patients over age 11 with distant metastases to brain [stage IV disease] would be considered poor risk and therefore not eligible for this trial)
• Patients with significant, pre-existing co-morbid respiratory disease that contraindicate the use of bleomycin are ineligible for the standard risk arms of the trial
• Female patients who are pregnant since fetal toxicities and teratogenic effects have been noted for several of the study drugs; a pregnancy test is required for female patients of childbearing potential; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Lactating females who plan to breastfeed their infants; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])

Major Inclusion Criteria:

1. Adults 18 years old or older. 2. Newly diagnosed epithelial adenocarcinoma of ovarian, fallopian tube or peritoneal origin FIGO Stage III or IV disease. 3. Histologic epithelial cell types: high grade serous adenocarcinoma, high grade endometrioid adenocarcinoma, undifferentiated carcinoma, clear cell adenocarcinoma, mixed epithelial carcinoma, or adenocarcinoma not otherwise specified (N.O.S.). 4. Completed debulking surgery (either primary debulking surgery or interval debulking surgery at the discretion of the investigator). Debulking surgery must be optimal, R1 or R0 (defined as R1, macroscopic no greater than 1 cm in diameter, or R0, microscopic or no evidence of tumor). 5. Preoperative serum CA- 125 levels ≥ 50 U/mL. 6. Adequate bone marrow function: 1. Absolute neutrophil count (ANC) greater than or equal to 1,500/µL 2. Platelets greater than or equal to100,000/µL 3. Hemoglobin greater than or equal to 8.0 g/dL (Note: Blood transfusion is permitted up to 48 hours before first dose of study treatment). 7. Adequate liver function: 1. Bilirubin < 1.5 times upper limit normal (ULN) 2. Lactate Dehydrogenase (LDH), SGOT/AST and SGPT/ALT < 2.5 times ULN 3. Albumin >3.5 g/dL 8. Adequate renal function: a. Creatinine less than or equal to1.5 times ULN 9. ECOG Performance Status of 0 or 1.

Major Exclusion Criteria:

1. BRCA1 or BRCA2 germline gene mutation test result with: 1. Positive, ambiguous or inconclusive result available within 28 days prior to starting study treatment, or 2. Known BRCA1 and BRCA2 somatic mutations, and known positive germline, or 3. Somatic Homologous Recombination Deficiency (HRD) who will receive PARP inhibitor front-line maintenance therapy. 2. Subjects with mucinous adenocarcinoma and low- grade adenocarcinoma. 3. Female subjects who are lactating and breastfeeding, or have a positive serum pregnancy test within 7 days prior to the first dose of study treatment (C1D1 for Cohort 1 or C4D1 for Cohort 2). 4. Active autoimmune disease, such as rheumatoid arthritis, systemic lupus erythematosus (SLE), ulcerative colitis, Crohn's Disease, multiple sclerosis (MS), or ankylosing spondylitis requiring active disease modifying treatment. 5. Known allergy to murine proteins or hypersensitivity to any of the excipients of the oregovomab, paclitaxel, or carboplatin. 6. Chronically treated with immunosuppressive drugs such as cyclosporine, adrenocorticotropic hormone (ACTH), etc. (see Appendix G). 7. Chronic therapeutic corticosteroid use, defined as > 5 days of prednisone or equivalent, with the exception of inhalers or those on a pre-planned steroid taper. (Note: Premedication with corticosteroids per institutional standard of care is allowed.) 8. Recognized acquired, hereditary, or congenital immunodeficiency disease, including cellular immunodeficiencies, hypogammaglobulinemia or dysgammaglobulinemia. 9. Anticipated treatment with any other anti-cancer medications, including bevacizumab, poly (ADP- ribose) polymerase (PARP) inhibitors, or any investigational agent(s) during the study.

Inclusion Criteria:

• Patient is female and ≥18 years of age.
• Patient has histologically confirmed diagnosis of EOC (ie, high-grade serous, endometrioid of any grade, clear cell), fallopian tube cancer, or primary peritoneal cancer.
• Patient has platinum-resistant/refractory disease, defined as disease progression within 180 days following the last administered dose of platinum therapy beyond first-line setting (resistant) or lack of response or disease progression while receiving the most recent platinum-based therapy (refractory). Patient must have progressed radiographically on or after their most recent line of anticancer therapy.
• Patient must have received at least 1 prior line of systemic anticancer therapy in the platinum sensitive setting, and no more than 5 prior lines of systemic anticancer therapy in the platinum-resistant setting. Patient must have received at least 1 line of therapy containing bevacizumab.
• Patient has at least one measurable lesion that qualifies as a target lesion based on RECISTv1.1.
• Patient is willing to undergo a pre-treatment tumor biopsy or provide qualifying archival tumor tissue.

Exclusion Criteria:

• Patient has primary platinum-refractory disease or primary platinum resistance, defined as disease progression during first-line platinum-based therapy (refractory) or disease progression <3 months after completion of first-line platinum-based therapy (resistant).
• Patient has histologically confirmed diagnosis of EOC with mucinous or carcinosarcoma subtype.
• Patient has nonepithelial tumor (eg, germline or stromal cell tumor) or ovarian tumor with low malignant potential (ie, borderline or low-grade serous tumor).
• Patient requires fluid drainage (eg, paracentesis, thoracentesis, pericardiocentesis) of ≥500 mL within 4 weeks of first dose of study drug.
• Patient has received prior IL-2-based or IL-15-based cytokine therapy; patient has had exposure, including intralesional, to IL-12 or analogs thereof.
• Patient has prior exposure to any anti-PD1/PD-L1 therapy.

Inclusion Criteria:

1. Patient must have advanced (FIGO 2014 Stage III or IV), persistent, or recurrent endometrial carcinoma, which is not likely to be curable by surgery or radiotherapy. Histologic confirmation of recurrent disease is required. For cases of persistent disease, histologic confirmation of the primary disease with radiologic evidence of progression is required. 2. Patients must have endometrioid histology (all grades allowed) based on hysterectomy or biopsy specimen (Hormone receptor status is not required for enrollment). Sites are required to report results of previous MMR, MSI, and ER/PR status testing in Medidata Rave if available. 3. All patients must have measurable disease. Measurable disease is defined by RECIST version 1.1. Measurable disease is defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded). Each lesion must be greater than or equal to 10mm when measured by CT, MRI or caliper measurement by clinical exam; or greater than or equal to 20mm when measured by chest x-ray. Lymph nodes must be greater than or equal to 15mm in short axis when measured by CT or MRI. Patient must have at least one "target lesion" to be used to assess response on this protocol as defined by RECIST 1.1. Tumors within a previously irradiated field will be designated as "non-target" lesions unless progression is documented or a biopsy is obtained to confirm persistence at least 90 days following completion of radiation therapy. 4. Prior chemotherapy in the adjuvant setting for Stage I, II, or III is permitted. Prior chemoradiotherapy for a pelvic recurrence is permitted. Note: Chemotherapy in the setting of Stage IV disease is permitted but the patient must be without evidence of disease at the completion of chemotherapy and have at least six months of progression-free survival since the completion of chemotherapy before detection of the recurrent cancer for which she is receiving treatment on this protocol. Prior immunotherapy and/or targeted therapy is allowed in addition to, in combination with, in lieu of, or subsequent to prior chemotherapy. Regardless of circumstances, no more than one prior chemotherapy regimen (including chemo-radiotherapy) is permitted, and no more than one additional systemic therapy is permitted. Hence, eligible patient may have received 0, 1, or 2 prior lines of systemic therapy and for women who received two prior lines of therapy, only one of them may have included chemotherapy. Patients who received prior chemotherapy, immunotherapy or targeted therapy must have recovered (Common Terminology Criteria for Adverse Events [CTCAE] Grade ≤1) from the acute effects of chemotherapy except for residual alopecia or Grade 2 peripheral neuropathy prior to enrollment. A washout period of at least 21 days is required between last systemic therapy dose and initiation of therapy. Patients who received radiotherapy must have completed and fully recovered from the acute effects of radiotherapy. A washout period of at least 14 days is required between end of radiotherapy and initiation of therapy. 5. Patient must be able to swallow oral medications. 6. Patient must have an ECOG performance status of 0 to 1. 7. Patients must have adequate organ and marrow function as defined below NOTE: Institutional/laboratory upper limit of normal = ULN Institutional/laboratory lower limit of normal = LLN Bone marrow function:
• Absolute neutrophil count (ANC) greater than or equal to 1500/mcl
• Platelets greater than or equal to 100,000 cells/mcl
• Hemoglobin greater than or equal to 8 g/dL (Patients may receive erythrocyte transfusions to achieve this hemoglobin level at the discretion of the investigator. Initial treatment must not begin earlier than the day after erythrocyte transfusion). Renal function: • Creatinine less than or equal to 1.5 x ULN Hepatic function:
• Bilirubin less than or equal to 1.5 x ULN (Patients with Gilbert's syndrome with a total bilirubin ≤2 times ULN and direct bilirubin within normal limits are permitted).
• ALT (alanine aminotransferase) and AST (aspartate aminotransferase) less than or equal to 3 x ULN
• Alkaline phosphatase less than or equal to 2.5 x ULN
• Albumin greater than or equal to 2.8 g/dL 8. Patients must have signed an approved informed consent and authorization permitting release of personal health information. 9. Patients must be at least 18 years of age. 10. Patients of childbearing potential must have a negative serum pregnancy test prior to the study entry and be practicing a highly effective form of contraception during the study treatment and for 8 weeks after stopping the treatment. Highly effective contraception methods include combination of any of the following (NOTE: Estrogen containing contraceptives are prohibited):
• Use of oral, injected, or implanted hormonal methods of contraception or;
• Placement of an intrauterine device (IUD) or intrauterine system (IUS);
• Barrier methods of contraception: condom or occlusive cap (diaphgram or cervical/vault caps) with spermicidal foam/gel/film/cream/vaginal suppository;
• Total abstinence or;
• Male/female sterilization. Women are considered post-menopausal and not of child-bearing potential if they have had 12 months of natural (spontaneous) amenorrhea with an appropriate clinical profile (e.g., age appropriate, history of vasomotor symptoms) or have had surgical bilateral oophorectomy (with or without hysterectomy) or tubal ligation at least six weeks prior to randomization. In the case of oophorectomy alone, only when the reproductive status of the woman has been confirmed by follow up hormone level assessment is she considered not of child-bearing potential. Exclusion criteria 1. Patients who have previously received any CDK4/6 inhibitor. 2. Patients with clear cell, serous, carcinosarcoma, mixed histology endometrial cancers, or uterine sarcomas. 3. Known intolerance or hypersensitivity to abemaciclib or letrozole. 4. Patients who have previously received hormonal therapy for endometrial cancer. 5. Patients with concomitant invasive malignancy or a history of other invasive malignancies, with the exception of non-melanoma skin cancer, are excluded if there is any evidence of other malignancy being present within the past five years. Patients are also excluded if their previous cancer treatment contraindicates this protocol. 6. Patients receiving chronic treatment with systemic steroids or another immunosuppressive agent. 7. Patients with active systemic bacterial infection (requiring intravenous [IV] antibiotics at time of initiating study treatment, fungal infection, or detectable viral infection (such as known human immunodeficiency virus positivity or with known active hepatitis B or C [for example, hepatitis B surface antigen positive]). Screening is not required for enrollment. 8. Patients with a serious pre-existing medical condition(s) that would preclude participation in this study (for example: interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, severe renal impairment (i.e. estimated creatinine clearance <30ml/min), history of major surgical resection involving the stomach or small bowel, or preexisting Crohn's disease or ulcerative colitis or pre-existing chronic condition resulting in baseline grade 2 or higher diarrhea). 9. Patients with a known history of cardiac disease. This includes:
• Uncontrolled hypertension, defined as systolic greater than 150mm Hg or diastolic greater than 90mm Hg despite antihypertensive medications
• Myocardial infarction or unstable angina within 6 months prior to registration.
• New York Heart Association (NYHA) Class II or greater congestive heart failure.
• History of serious ventricular arrhythmia (i.e. ventricular tachycardia or ventricular fibrillation) or serious cardiac arrhythmia requiring medication, syncope of cardiovascular etiology or sudden cardiac arrest. This does not include asymptomatic atrial fibrillation with controlled ventricular rate.
• Cerebrovascular accident (CVA, stroke), transient ischemic attack (TIA) within 6 months prior to the first date of study therapy. 10. Patients who are pregnant or breast-feeding. 11. Patients with known central nervous system metastases. 12. Patients with known human immunodeficiency virus (HIV) infection. 13. Patients with an impairment of gastrointestinal function or gastrointestinal disease that may significantly alter the absorption of abemaciclib (i.e. ulcerative disease; uncontrolled nausea, vomiting and/or diarrhea; malabsorption syndrome; clinical signs and symptoms of gastrointestinal obstruction; and/or patients who require parenteral hydration and/or nutrition). 14. Patients who plan to receive live attenuated vaccines within 1 week of start of abemaciclib and during the study. Patients should also avoid close contact with others who have received live attenuated vaccines. Examples of live attenuated vaccines include intranasal influenza, measles, mumps, rubella, oral polio, BCG, yellow fever, varicella, and TY21a typhoid vaccines. 15. Patients with active bleeding or pathologic conditions that carry high risk of bleeding such as known bleeding disorder or coagulopathy. 16. Patients with history of unprovoked venous thrombosis unless taking anticoagulation treatment for duration of trial. 17. Patients who are currently part of or have participated in any clinical investigation with an investigational drug within 30 days prior to dosing.

Inclusion Criteria:

1. Histologically or cytologically confirmed metastatic or refractory/recurrent HPV-16+ cancer. 2. Tumor with HPV16 genotype as determined by testing performed in a CLIA certified laboratory. 3. HLA-A*02:01 allele as determined by testing performed in a Clinical Laboratory Improvement Amendments (CLIA) certified laboratory. Participants may be enrolled based on low resolution typing (i.e., HLA-A*02) but the HLA-A*02:01 allele type must be confirmed prior to apheresis. 4. Measurable disease as assessed by RECIST Criteria Version 1.114. 5. Age ≥ 18 years. 6. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 at screening. 7. Must have received prior first line standard therapy or have declined standard therapy. 8. Standard treatment options for first and second-line therapy must be presented and formally declined (Appendix VII). 9. Patients with three or fewer brain metastases that have been treated with surgery or stereotactic radiosurgery are eligible. Lesions that have been treated with stereotactic radiosurgery must be clinically stable for one month before protocol treatment. Patients must be fully recovered from surgery. 10. Negative pregnancy test for women under 55 and all women who have had a menstrual period in the last 12 months. A pregnancy tests is not required for women who have had a bilateral oophorectomy or hysterectomy. 11. Men and women of child-bearing potential must agree to use adequate contraception (i.e., intrauterine device, hormonal barrier method of birth control; abstinence; tubal ligation or vasectomy) prior to study entry and for four months after treatment. Should a women become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. 12. Seronegative for HIV antibody, hepatitis B antigen, and hepatitis C antibody. If a hepatitis C antibody test is positive, then testing for antigen by RT-PCR for Hepatitis C (HCV) RNA must be negative. 13. Participants must have organ and marrow function as defined below: 1. Leukocytes > 3,000/microliter (mcL) 2. Absolute neutrophil count > 1,500/mcL 3. Platelets > 100,000/mcL 4. Hemoglobin > 8.0 g/dL 5. Total bilirubin within normal institutional limits except in participants with Gilbert's Syndrome who must have a total bilirubin < 3.0 mg/dL. 6. Serum aspartate transferase (AST) (SGOT)/alanine transaminase (ALT) (SGPT) < 2.5 x upper limit of normal (ULN) 7. Calculated creatinine clearance (CrCl) >50 mL/min/1.73 m2for participants with creatinine levels above institutional normal (by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation). 8. international normalized ratio (INR) or activated partial thromboplastin time ( aPTT) ≤1.5 X ULN unless the subject is receiving anticoagulant therapy. Subjects on anticoagulant therapy must have a PT or aPTT within therapeutic range and no history of severe hemorrhage. 14. More than four weeks must have elapsed since any prior systemic therapy at the time the patient receives the E7 TCR cells. 15. Participants must be able to understand and be willing to sign the written informed consent document. 16. Participants must agree to participate in protocol Cancer Institute of New Jersey (CINJ) 192103 (Pro2021002307) for gene therapy long term follow up and in protocol CINJ 192002 (Pro2021000281) for biospecimen collection study.

Inclusion Criteria:

• Federation of Gynecology and Obstetrics (FIGO) 2009 stage IA-IVB, non-recurrent, chemotherapy (chemo)-naive, HER2-positive endometrial serous carcinoma or endometrial carcinosarcoma
• Histologic confirmation of the original primary tumor is required. Submission of surgical pathology report (or endometrial biopsy pathology report in patients who never undergo hysterectomy) is required
• Patients must be within 8 weeks of primary surgery (or endometrial biopsy in patients who never undergo hysterectomy) at the time of study registration
• Patients may have measurable disease, non-measurable disease, or no measurable disease. In patients with measurable disease, lesions will be defined and monitored by RECIST v 1.1. Measurable disease is defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded). Each lesion must be >= 10 mm when measured by computed tomography (CT) or magnetic resonance imaging (MRI). Lymph nodes must be >= 15 mm in short axis when measured by CT or MRI
• For patients with uterine-confined (stage I) disease, the tumor must be invasive into the myometrium. Any amount of myoinvasion is acceptable for eligibility. Patients with non-invasive disease, endometrial intraepithelial carcinoma alone, or disease confined to a polyp will be excluded
• Additionally, patients must have the following histologic types to be eligible:
• Serous adenocarcinoma (may include =< 10% non-serous histology)
• Carcinosarcoma with serous epithelial component (only the serous component needs to be HER2 positive; may include =< 10% non-serous histology)
• In cases where determination of serous is equivocal or challenging, aberrant p53 immunohistochemistry (IHC) (defined as overexpression of p53 compared to internal controls) will be sufficient for inclusion
• All patients must have tumors that are HER2 positive as defined by American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) 2018 Breast Cancer guidelines (https://documents.cap.org/documents/algorithim-evaluation-her2.pdf. In general HER2 positivity is defined as any of the following:
• 3+ immunohistochemistry (IHC),
• 2+ IHC with positive in situ hybridization (ISH)
• Average HER2 copy number >= 6.0 signals/cell
• Average HER2 copy number >= 4.0 and < 6.0 signals/cell, with concurrent IHC 3+
• HER2/CEP17 ratio >= 4.0 signals/cell
• HER2/CEP 17 ratio >= 2.0 and < 4.0, with concurrent IHC 3+ IHC and ISH testing will be done locally, at each participating institution and interpreted by local pathologists. Alternatively, patients could be eligible if next generation sequencing (NGS) demonstrates HER2 (ERBB2) amplification. NGS testing can be performed through any designated labs as per the National Cancer Institute (NCI) MATCH/NCI Combo-MATCH trial (https://ecog-acrin.orgci-match-eay131-designated-labs). Pathology report showing results of institutional HER2 testing (or NGS testing results) must be submitted. Sites must submit all results available (IHC, ISH, and NGS)
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2
• Age >= 18
• Platelets >= 100,000/mcl (within 14 days prior to registration)
• Absolute neutrophil count (ANC) >= 1,500/mcl (within 14 days prior to registration)
• Creatinine =< 1.5 x institutional/laboratory upper limit of normal (ULN) or estimated Glomerular filtration rate (eGFR) >= 50 mL/min using either the Cockcroft-Gault equation, the Modification of Diet in Renal Disease Study, or as reported in the comprehensive metabolic panel/basic metabolic panel (eGFR). (within 14 days prior to registration)
• Total serum bilirubin level =< 1.5 x ULN (patients with known Gilbert's disease who have bilirubin level =< 3 x ULN may be enrolled) (within 14 days prior to registration)
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 3 x ULN (within 14 days prior to registration)
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months of registration are eligible for this trial
• Although the uterus will have been removed in the vast majority of patients, for patients of child-bearing potential: negative urine or serum pregnancy test. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test is required. Patients will be considered of non-reproductive potential if they are either:
• Postmenopausal (defined as at least 12 months with no menses without an alternative medical cause; in women < 45 years of age, a high follicle stimulating hormone [FSH] level in the postmenopausal range may be used to confirm a postmenopausal state in women not using hormonal contraception or hormonal replacement therapy. In the absence of 12 months of amenorrhea, a single FSH measurement is insufficient); OR
• Have had a hysterectomy and/or bilateral oophorectomy, bilateral salpingectomy or bilateral tubal ligation/occlusion at least 6 weeks prior to registration
• Have a congenital or acquired condition that prevents childbearing
• Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. NOTE: Patients with prior anthracycline exposure are NOT eligible
• Patients with evidence of chronic hepatitis B virus (HBV) infection must have an undetectable HBV viral load on suppressive therapy, if indicated
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
• Patients with treated brain metastases are eligible if follow-up brain imaging after central nervous system (CNS)-directed therapy shows no evidence of progression
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry and, for patients treated in the United States (U.S.), authorization permitting release of personal health information

Exclusion Criteria:

• Prior Therapy:
• Patients must NOT have received prior chemotherapy, biologic therapy, or targeted therapy for treatment of endometrial carcinoma
• Patients must NOT have received prior radiation therapy for treatment of endometrial carcinoma. Prior radiation includes external beam pelvic radiation therapy, external beam extended field pelvic/para-aortic radiation therapy, and/or intravaginal brachytherapy
• NOTE: Vaginal brachytherapy for treatment of endometrial cancer is permitted during study treatment. Planned use of vaginal brachytherapy must be declared at time of registration
• Patients may have received prior hormonal therapy for treatment of endometrial carcinoma. All hormonal therapy must be discontinued at least one week prior to registration
• Patients may not have a planned interval cytoreduction or hysterectomy, prior to documentation of progression, after study registration
• Patients may not have planned external beam radiotherapy, prior to documentation of progression, after study registration
• Significant cardiovascular disease including:
• Uncontrolled hypertension, defined as systolic > 150 mm Hg or diastolic > 90 mm Hg despite antihypertensive medications
• Myocardial infarction or unstable angina within 6 months prior to registration
• New York Heart Association functional classification II, III or IV
• Serious cardiac arrhythmia requiring medication. This does not include asymptomatic, atrial fibrillation with controlled ventricular rate
• Significant lung disease: dyspnea at rest grade 2 or greater (resulting from extensive tumor involvement or other causes), pneumonitis grade 2 or greater, interstitial lung disease grade 2 or greater, idiopathic pulmonary fibrosis, cystic fibrosis, Aspergillosis, active tuberculosis, or history of opportunistic infections (pneumocystis pneumonia or cytomegalovirus pneumonia)
• Patients with uncontrolled intercurrent illness including, but not limited to: ongoing or active infection (except for uncomplicated urinary tract infection), uncontrolled interstitial lung disease, symptomatic congestive heart failure, or psychiatric illness/social situations that would limit compliance with study requirements
• Treatment with strong CYP2C8 or CYP3A4 inhibitors or inducers within 14 days or 5 drug-elimination half-lives, whichever is longer, prior to registration
• Women who are unwilling to discontinue nursing

Inclusion Criteria:

• STEP 1 REGISTRATION AND RANDOMIZATION
• Patients must be >= 18 years of age
• Patient must have the ability to understand and the willingness to sign a written informed consent document. Patients with impaired decision-making capacity (IDMC) who have a legally authorized representative (LAR) or caregiver and/or family member available will also be considered eligible
• Patient must have a diagnosis of high grade upper tract urothelial carcinoma proven by biopsy within 12 weeks (84 days) prior to registration/randomization with one of the following:
• Upper urinary tract mass on cross-sectional imaging or
• Tumor directly visualized during upper urinary tract endoscopy before referral to medical oncology
• NOTE: Biopsy is standard of care (SOC) and required for enrollment to study. This is vital for best practice
• Leukocytes >= 3,000/mcL (obtained =< 14 days prior to registration/randomization)
• Platelets >= 100,000/mcL (obtained =< 14 days prior to registration/randomization)
• Total bilirubin =< 1.5 x institutional upper limit of normal (ULN) (or =< 2.5 x ULN for patients with Gilbert's disease) (obtained =< 14 days prior to registration/randomization)
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 2.5 x institutional ULN (obtained =< 14 days prior to registration/randomization)
• Hemoglobin (Hgb) >= 9 g/dL (obtained =< 14 days prior to registration/randomization)
• NOTE: Packed red blood transfusion is allowed to achieve this parameter as per treating investigator
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months prior to registration/randomization are eligible for this trial
• NOTE: These patients must be stable on their anti-retroviral regimen with evidence of at least two undetectable viral loads within the past 6 months on the same regimen; the most recent undetectable viral load must be within the past 12 weeks. They must have a CD4 count of greater than 250 cells/mcL over the past 6 months on this same anti-retroviral regimen and must not have had a CD4 count < 200 cells/mcL over the past 2 years, unless it was deemed related to the cancer and/or chemotherapy induced bone marrow suppression. They must not be currently receiving prophylactic therapy for an opportunistic infection and must not have had an opportunistic infection within the past 6 months
• NOTE: For patients who have received chemotherapy in the past 6 months, a CD4 count < 250 cells/mcL during chemotherapy is permitted as long as viral loads were undetectable during this same chemotherapy. They must have an undetectable viral load and a CD4 count >= 250 cells/mcL within 7 days of registration/randomization
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated
• NOTE: Testing for HIV, hepatitis B or hepatitis C is not required unless clinically indicated
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and have undetectable viral load. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
• Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, patients should be class 2B or better
• Patient must have a body weight of > 30 kg
• Patient must have life expectancy of >= 12 weeks
• Patient must have creatinine clearance > 15 ml/min as by Crockroft-Gault formula or 24-hour creatinine clearance within 28 days prior to registration/randomization
• NOTE: Patients will be assigned to cisplatin-ineligible and cisplatin-eligible cohorts based on their creatinine clearance, Eastern Cooperative Oncology Group (ECOG) performance status, and grade (if any) of peripheral neuropathy and/or hearing loss in keeping with SOC cisplatin contraindications. Patients that are cisplatin-eligible will be randomized to either Arm A or Arm B
• Patients that meet any of the following criteria will be registered and assigned to the cisplatin-ineligible Arm C if they meet other eligibility criteria:
• Creatinine clearance > 15 ml/min and =< 50 ml/min or hearing loss grade >= 3, or neuropathy >= 2, or ECOG PS 2
• Patient must have an absolute neutrophil count (ANC) >= 1,000/mcL obtained =< 14 days prior to registration
• Patient must have ECOG performance status 0-2
• Patients that meet the following criteria will be randomized to the cisplatin-eligible Arm A or Arm B:
• Patient must have creatinine clearance of > 50ml/min, PS ECOG 0-1, absence of hearing loss grade >= 3, and/or neuropathy >= 2
• Patient must have an absolute neutrophil count (ANC) >= 1,500/mcL obtained =< 14 days prior to randomization
• Patient must have left ventricular ejection fraction (LVEF) >= 50% by (either multigated acquisition scan [MUGA] or 2-D echocardiogram) obtained within obtained within 28 days prior to randomization

Exclusion Criteria:

• Patients must not have any component of small celleuroendocrine carcinoma. Other variant histologic types are permitted provided the predominant (>= 50%) subtype is urothelial carcinoma
• Patients must not be pregnant or breast-feeding due to the potential harm to an unborn fetus and possible risk for adverse events in nursing infants with the treatment regimens being used. All patients of childbearing potential must have a blood test or urine study within 14 days prior to registration to rule out pregnancy. A patient of childbearing potential is defined as any patient, regardless of sexual orientation or whether they have undergone tubal ligation, who meets the following criteria: 1) has achieved menarche at some point, 2) has not undergone a hysterectomy or bilateral oophorectomy; or 3) has not been naturally postmenopausal (amenorrhea following cancer therapy does not rule out childbearing potential) for at least 24 consecutive months (i.e., has had menses at any time in the preceding 24 consecutive months)
• Patients of childbearing potential and sexually active patients must not expect to conceive or father children, either by using accepted and effective method(s) of contraception or by abstaining from sexual intercourse from the time of registration, while on study treatment and for at least 6 months after the last dose of protocol treatment
• Patients must have no evidence of metastatic disease or clinically enlarged regional lymph nodes (>= 1.5 cm short axis) on imaging required within 28 days prior to registration (Non-regional findings >=1.5 cm short axis that in the opinion of the investigator are not concerning for involvement based on radiographic characteristics, chronicity, avidity on positron emission tomography (PET) or other imaging or other criteria can be eligible based on investigator discretion).
• NOTE: Patients with elevated alkaline phosphatase, calcium or suspicious bone pain/tenderness can also undergo baseline bone scans to evaluate for bone metastasis at the discretion of local provider.
• Patient must meet below criteria for prior/current malignancy history:
• Non-urothelial cancer malignancy history:
• Patient must not have another active (or within two years) second malignancy other than resected non-melanoma skin cancers, resected in situ breast, cervical or other in situ carcinoma, and either clinically insignificant per the investigator (e.g. =< Gleason 3+4) on active surveillance (or watchful waiting) or previously treated prostate cancer with no rising prostate specific antigen (PSA) and no plan to treat
• NOTE: Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. Patients in whom concomitant or prior bladder/urethra predominant (>= 50%) urothelial carcinoma have been surgically resected and demonstrated to be only non-invasive cancer (< cT1N0) are eligible regardless of time elapsed
• Urothelial cancer malignancy history:
• Patient may have a history of resectable urothelial cancer as long as patients meet one of the following:
• T0, Ta or Tis at any time
• T1-4a N0 and no evidence of disease (NED) for more than 2 years from the latest therapy [e.g., radical surgery, transurethral resection of bladder tumor (TURBT), radiation, chemotherapy (neoadjuvant or adjuvant, or with radiation)]. Prior immune checkpoint inhibitor is not allowed.
• Patient with history of >= pT4b, N+, and/or M1 is not eligible.
• NOTE: Patients in whom concomitant or prior bladder/urethra predominant (>= 50%) urothelial carcinoma have been surgically resected and demonstrated to be only Ta or carcinoma in situ (CIS) (< cT1 N0) are eligible regardless of time elapsed
• Patient must not have any uncontrolled illness including, but not limited to, ongoing or active infection including tuberculosis (clinical evaluation that includes clinical history, physical examination and radiographic findings, and tuberculosis [TB] testing in line with local practice), symptomatic congestive heart failure (CHF), myocardial infarction (MI) in last three months, or unstable angina pectoris, significant uncontrolled cardiac arrhythmia, clinically relevant liver cirrhosis, interstitial lung disease, or psychiatric illness/social situations that would limit compliance with study requirements
• Patient must not have received prior radiation therapy to >= 25% of the bone marrow for other diseases
• Patient must not have received prior systemic anthracycline therapy
• NOTE: Patients who have received prior intravesical chemotherapy at any time for non-muscle invasive urothelial carcinoma of the bladder are eligible
• Patient must not have either history of or active autoimmune disease requiring immunosuppressive therapy within 2 years prior to registration/randomization or any history of inflammatory bowel disease (inflammatory bowel disease [IBD], colitis, or Crohn's disease), neuromuscular autoimmune condition, immune-related pneumonitis or interstitial lung disease. Patients with well-controlled hyper/hypothyroidism, celiac controlled by diet alone, diabetes mellitus type I, vitiligo, alopecia, psoriasis, eczema, lichen planus, or similar skin/mucosa condition are eligible
• Patient must not be on or have used immunosuppressive medication within 14 days prior to the first dose of durvalumab. The following are exceptions to this criterion:
• Intranasal, inhaled, intra-auricular, topical steroids, or local steroid injections (e.g. intra-articular injection
• Systemic corticosteroids at physiologic doses not to exceed 10 mg/day of prednisone or its equivalent at the time of enrollment
• Steroids as premedications for hypersensitivity reactions (e.g. computed tomography [CT] scan premedication)
• Patient must not have received live attenuated vaccine within 30 days prior to the first dose of durvalumab, while on protocol treatment and within 30 days after the last dose of durvalumab
• Patient must not have had a major surgical procedure within 28 days prior to registration/randomization
• NOTE: Cystoscopy/ureteroscopy, stent placement or nephrostomy tube is not considered major surgery
• Patient must not have history of allogenic organ transplantation

Inclusion Criteria:

1. Age ≥ 11 years and ≤ 45 years on the date of randomisation 2. Histologically or cytologically confirmed germ cell tumour (non-seminoma or seminoma); or Exceptionally raised tumour markers (AFP ≥ 1000ng/mL and/or HCG ≥ 5000 IU/L) without histologic or cytologic confirmation in the rare case where pattern of metastases consistent with GCT, high tumour burden, and a need to start therapy urgently 3. Primary arising in testis, ovary, retro-peritoneum, or mediastinum 4. Metastatic disease or non-testicular primary 5. Intermediate or poor prognosis as defined by IGCCC classification3 (modified with different LDH criteria for intermediate risk non-seminoma, and inclusion of ovarian primaries). (See protocol for more information). 6. Adequate bone marrow function with ANC ≥1.0 x 10^9/L, Platelet count ≥100 x 10^9/L 7. Adequate liver function where bilirubin must be ≤1.5 x ULN, except participants with Gilbert's Syndrome where bilirubin must be ≤2.0 x ULN; ALT and AST must be ≤2.5 x ULN, except if the elevations are due to hepatic metastases, in which case ALT and AST must be ≤ 5 x ULN 8. Adequate renal function with estimated creatinine clearance of ≥60 ml/min according to the Cockcroft-Gault formula, unless calculated to be < 60 ml/min or borderline in which case GFR should be formally measured, eg. with EDTA scan 9. ECOG Performance Status of 0, 1, 2, or 3 10. Study treatment both planned and able to start within 14 days of randomisation. 11. Willing and able to comply with all study requirements, including treatment, timing and nature of required assessments 12. Able to provide signed, written informed consent

Exclusion Criteria:

1. Other primary malignancy (EXCEPT adequately treated non-melanomatous carcinoma of the skin, germ cell tumour, or other malignancy treated at least 5 years previously with no evidence of recurrence) 2. Previous chemotherapy or radiotherapy, except if patient has pure seminoma relapsing after adjuvant radiotherapy or adjuvant chemotherapy with 1-2 doses of single agent carboplatin or if patient has non-seminoma and poor prognosis by IGCCC criteria in the rare case where low-dose induction chemotherapy is given prior to registration because patient is not fit enough to receive protocol chemotherapy (eg. organ failure, vena cava obstruction, overwhelming burden of disease). In these instances acceptable regimens include cisplatin 20 mg/m^2 days 1-2 and etoposide 100 mg/m^2 days 1-2; carboplatin AUC 3 days 1-2 and etoposide 100 mg/m^2 days 1-2; or baby-BOP. Patients must meet all other inclusion and exclusion criteria at the time of registration. Additionally participants who need to start therapy urgently prior to completing study-specific baseline investigations may commence study chemotherapy prior to registration and randomisation. Such patients must be discussed with the coordinating centre prior to registration, and must be registered within 10 days of commencing study chemotherapy. 3. Significant cardiac disease resulting in inability to tolerate IV fluid hydration for cisplatin 4. Significant co-morbid respiratory disease that contraindicates the use of bleomycin 5. Peripheral neuropathy ≥ grade 2 or clinically significant sensorineural hearing loss or tinnitus 6. Concurrent illness, including severe infection that may jeopardize the ability of the participant to undergo the procedures outlined in this protocol with reasonable safety 7. Inadequate contraception. Men must use 2 effective methods of contraception, including use of a condom, during chemotherapy and for a year after completing chemotherapy. 8. Known allergy or hypersensitivity to any of the study drugs 9. Presence of any psychological, familial, sociological or geographical condition that in the opinion of the investigator would hamper compliance with the study protocol and follow-up schedule, including alcohol dependence or drug abuse The above inclusion and exclusion criteria will apply to stage 1 (n=150) and stage 2 (n=500 including stage 1) of the study. All sites will participate in both stages of the study with the exception of the Children's Oncology Group who will be participate in stage 1 only.

Inclusion Criteria:

• Has histologically-confirmed International Federation of Gynecology and Obstetrics (FIGO) Stage III or Stage IV HGSOC, primary peritoneal cancer, or fallopian tube cancer.
• Is a candidate for carboplatin and paclitaxel chemotherapy, to be administered in the neoadjuvant and adjuvant setting.
• Is a candidate for interval debulking surgery.
• Is able to provide archival tissue or newly obtained core, incisional, or excisional biopsy of a tumor lesion.
• Has adequate organ functions.

Exclusion Criteria:

• Has a non-HGSOC histology.
• Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease.
• Has a known additional malignancy that is progressing or has required active treatment within the past 3 years.
• Has received prior treatment for any stage of OC, including radiation or systemic anticancer therapy.
• Planned or has been administered intraperitoneal chemotherapy as first-line therapy.
• Has received prior therapy with an anti-programmed cell death 1 protein (PD-1), anti-programmed cell death 1 ligand 1 (PD-L1), anti-programmed cell death 1 ligand 2 (PD-L2), anti-immunoglobulin-like transcript 4 (ILT4), or anti-human leukocyte antigen (HLA)-G agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor.
• Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention.
• Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study intervention.
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior the first dose of study medication.
• Has known active Central Nervous System (CNS) metastases and/or carcinomatous meningitis.
• Has severe hypersensitivity to pembrolizumab, carboplatin, paclitaxel (or docetaxel, if applicable), Avastin or biosimilar (if using) and/or any of their excipients.
• Has an active autoimmune disease that has required systemic treatment in past 2 years.
• Has an active infection requiring systemic therapy.
• Has a known history of human immunodeficiency virus (HIV) infection.
• Has a known history of hepatitis B or known active hepatitis C virus infection.
• Has received colony-stimulating factors within 4 weeks prior to receiving study intervention on Day 1 of Cycle 1.
• Has had surgery <6 months prior to Screening to treat borderline ovarian tumors, early-stage OC, or early-stage fallopian tube cancer.
• Has a known psychiatric or substance abuse disorder that would interfere with the participant's ability to cooperate with the requirements of the study.
• Has current, clinically relevant bowel obstruction.
• Has a history of hemorrhage, hemoptysis, or active gastrointestinal (GI) bleeding within 6 months prior to randomization.
• Has uncontrolled hypertension.
• Has had an allogenic tissue/solid organ transplant.
• .Has either had major surgery within 3 weeks of randomization or has not recovered from any effects of any major surgery.