Key Inclusion Criteria:

1. Have documented CD20+ aggressive B-NHL, with disease that has progressed after at least 2 lines of systemic therapy containing an anti-CD20 antibody and an alkylating agent. 2. Measurable disease on cross sectional imaging as defined in the protocol 3. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 4. Adequate bone marrow, renal and hepatic function as defined in the protocol 5. During dose expansion phase of the study, participant should be willing to undergo mandatory tumor biopsies, if in the opinion of the investigator, the participant has an accessible lesion that can be biopsied without significant risk to the participant.

Key Exclusion Criteria:

1. Prior treatments with allogeneic stem cell transplantation or solid organ transplantation, treatment with anti-CD20 x anti- CD3 bispecific antibody, such as odronextamab 2. Diagnosis of mantle cell lymphoma (MCL) 3. Primary central nervous system (CNS) lymphoma or known involvement by non-primary CNS lymphoma 4. Treatment with any systemic anti-lymphoma therapy within 5 half-lives or within 14 days prior to first administration of study drug, whichever is shorter 5. Standard radiotherapy within 14 days of first administration of study drug. 6. Continuous systemic corticosteroid treatment with more than 10 mg per day of prednisone or corticosteroid equivalent within 72 hours of start of odronextamab 7. Co-morbid conditions, as described in the protocol 8. Infections, as described in the protocol 9. Allergy/hypersensitivity: Known hypersensitivity to both allopurinol and rasburicaseNOTE: Other protocol defined inclusion / exclusion criteria apply

Key Inclusion Criteria

• Participant must be greater than or equal to (>=) 18 years of age, at the time of signing informed consent
• All participants must have relapsed or refractory disease for each histologic subtype
• Mature aggressive large B cell NHL and Follicular Lymphoma Grade 3b: Participants must have >= 2 lines of systemic therapy or >=1 line of systemic therapy in case of participants ineligible for high-dose chemotherapy and autologous Hematopoietic stem cell transplantation (HSCT). Participants also must have had exposure to an anthracycline and an anti-CD20 targeted agent
• Follicular lymphoma Grade 1-3a and Marginal Zone Lymphoma: Participants must have >=2 prior lines of anti-neoplastic systemic therapy. Participants also must have prior exposure to an anti-CD20 monoclonal antibody
• Tumor must be cluster of differentiation (CD) 20 positive
• Measurable disease as defined by Lugano 2014 classification
• Eastern Cooperative Oncology Group (ECOG) performance status of either 0 or 1

Key Exclusion Criteria

• Diagnosis of Human herpes virus (HHV) 8-positive Diffuse large B Cell lymphoma (DLBCL)
• Prior allogeneic Hematopoietic stem cell transplantation (HSCT)
• Autologous stem cell transplant within 12 weeks of chimeric antigen receptor (CAR) T cell infusion
• Uncontrolled active infections
• History of deep vein thrombosis or pulmonary embolism within six months of infusion (except for line associated deep vein thrombosis [DVT])
• History of stroke, unstable angina, myocardial infarction, congestive heart failure ( New York Heart Association [NYHA] Class III or IV), severe cardiomyopathy or ventricular arrhythmia requiring medication or mechanical control within 6 months of screening
• History of a seizure disorder, cerebrovascular ischemia/hemorrhage, dementia, cerebellar disease or neurodegenerative disorder
• Known history or prior diagnosis of optic neuritis or other immunologic or inflammatory disease affecting the central nervous system
• Active central nervous system (CNS) involvement by malignancy
• Current active liver or biliary disease (except for Gilbert's syndrome or asymptomatic gallstones)

• Participant must be greater than or equal to (>=) 18 years of age, at the time of signing informed consent
• Diagnosis of mature aggressive large B cell non-Hodgkin lymphoma or follicular lymphoma
• Tumor must be histologically confirmed cluster of differentiation (CD)19 and/or CD20 positive
• Must have relapsed or refractory disease with the following indications for each histologic subtype: Mature aggressive large B cell non-Hodgkin lymphoma (NHL) and follicular lymphoma Grade 3b: Participants must have >= 2 lines of systemic therapy, or >= 1 line of systemic therapy for participants who are ineligible for autologous stem cell transplant; Follicular lymphoma Grade 1-3a and marginal zone lymphoma: Participants must have >= 2 prior lines of anti-neoplastic systemic therapy. Participants also must have prior exposure to an anti-CD20 monoclonal antibody
• Measurable disease as defined by Lugano 2014 classification
• Eastern cooperative oncology group (ECOG) performance status of either 0 or 1

Exclusion Criteria

• Diagnosis of Human herpes virus (HHV) 8-positive diffuse large B Cell lymphoma (DLBCL)
• Prior allogeneic hematopoietic stem cell transplantation (HSCT)
• Autologous stem cell transplant within 12 weeks of chimeric antigen receptor (CAR) T cell infusion
• Uncontrolled active infections
• History of deep vein thrombosis or pulmonary embolism within six months of infusion (except for line associated deep vein thrombosis [DVT])
• History of stroke, unstable angina, myocardial infarction, congestive heart failure New York Heart Association (NYHA) Class III or IV, severe cardiomyopathy or ventricular arrhythmia requiring medication or mechanical control within 6 months of screening
• History of a seizure disorder, cerebrovascular ischemia/hemorrhage, dementia, cerebellar disease or neurodegenerative disorder
• Known history or prior diagnosis of optic neuritis or other immunologic or inflammatory disease affecting the central nervous system
• Current active liver or biliary disease (except for Gilbert's syndrome or asymptomatic gallstones)

Inclusion Criteria:

1. Ability to understand and the willingness to sign a written informed consent document and to comply with the study protocol procedures. 2. Age ≥18 years at the time of signing informed consent. Because no dosing or adverse event data are currently available on the use of mosunetuzumab in patients <18 years of age, they are excluded from this study. 3. Histologically confirmed diagnosis of:
• follicular lymphoma (grade 1, 2, 3a, or not otherwise specified) or
• marginal zone lymphoma (nodal, extranodal, or splenic), according to 2016 WHO classification and confirmed to express the CD20 antigen by immunohistochemistry or flow cytometry. Patients in whom definitive pathologic subtype of FL/MZL is undetermined due to limited biopsy material can be enrolled if in the investigator's opinion integrated clinicopathologic data are consistent with the eligible diagnosis. 4. Agreement to provide, if available, lymphoma tissue for correlative analyses. 5. At least one bi-dimensionally measurable nodal lesion, defined as >1.5 cm in its longest dimension, or one bi-dimensionally measurable extranodal lesion, defined as >1.0 cm in its longest diameter; with the exception of splenic MZL, which must be evaluable using the International SMZL Group criteria. 6. No prior systemic therapy for B-cell lymphoma, except for palliative corticosteroids; prior local therapy (surgery, radiation therapy, or antibiotics) is allowed. 7. Indication to start systemic therapy for lymphoma:
• Patients with FL must meet one of the GELF criteria:
• any mass ≥7 cm (except spleen);
• at least 3 nodes >3 cm in diameter;
• symptomatic spleen enlargement;
• local symptoms or compromise of normal organ function due to tumor mass;
• presence of ascites or pleural effusion;
• presence of B symptoms (fever, night sweats, or unintentional weight loss of >10% over ≤6 months);
• serum lactate dehydrogenase or beta-2-microglobulin above upper limit of normal;
• cytopenias due to underlying lymphoma (i.e., absolute neutrophil count <1.0 × 109/L, hemoglobin <10 g/dL, and/or platelet count <100 × 109/L).
• Patients with MZL must have an indication to start therapy as assessed by the investigator. 8. Performance status ECOG 0, 1, or 2. 9. Adequate hematologic function (unless due to underlying lymphoma as established by bone marrow involvement or splenomegaly):
• hemoglobin ≥9 g/dL,
• absolute neutrophil count ≥1.0 x 109/L,
• platelet count ≥75 x 109/L. 10. Glomerular filtration rate (GFR) ≥40 mL/min/1.73m2 using the Mayo Quadratic Formula. 11. The effects of mosunetuzumab on the developing human fetus are unknown. For this reason and because lenalidomide used in this trial is known to be teratogenic, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) and refrain from donating eggs or sperm throughout the treatment and for 3 months after the last dose of trial therapy. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. 12. Agreement to enroll in and comply with all local requirements of the REVLIMID® (lenalidomide) Risk Evaluation and Mitigation Strategy (REMS®) program for the purpose of lenalidomide acquisition.

Exclusion Criteria:

1. Grade 3b follicular lymphoma or transformed lymphoma. 2. Prior treatment with any anti-CD20 antibody or lenalidomide for lymphoma. 3. Prior stem cell transplantation (autologous or allogeneic) or prior solid organ transplantation. 4. History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies or known sensitivity or allergy to murine products. 5. Known NYHA class 3/4 congestive heart failure, LVEF <40%, myocardial infarction within 6 months prior to enrollment, unstable angina, or unstable arrhythmia. 6. Chronic obstructive pulmonary disease (COPD) requiring oral corticosteroids or chronic oxygen. 7. History of autoimmune disease, including, but not limited to myasthenia gravis, myositis, autoimmune hepatitis, idiopathic pulmonary fibrosis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipid syndrome, granulomatosis with polyangiitis, Guillain-Barré syndrome, multiple sclerosis, vasculitis, or glomerulonephritis, with the exception of: hypothyroidism (on stable dose of thyroid replacement therapy), asthma managed with inhaled medications only; type 1 diabetes mellitus on stable insulin regimen, Sjögren syndrome, immune thrombocytopenia or autoimmune hemolytic anemia that does not require systemic therapy; dermatologic condition (including eczema, psoriasis, lichen simplex chronicus, or vitiligo) with skin manifestations with rash covering <10% of body surface area and not requiring treatment other than low-potency topical corticosteroids for >12 months prior to registration. 8. Use of any systemic immunosuppressive medications (including, but not limited to, cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor agents) with the exception of corticosteroid treatment using <10 mg/day prednisone or equivalent within 2 weeks prior to first treatment; a brief course of palliative corticosteroids at higher doses (prednisone up to 100 mg daily, for up to 7 days) is allowed, but must be completed at least 7 days before the first dose of mosunetuzumab. 9. Any of the following conditions:
• active bacterial infection requiring antibiotics
• known or suspected chronic active Epstein Barr virus (CAEBV) infection
• history of hemophagocytic lymphohistiocytosis (HLH)
• confirmed progressive multifocal leukoencephalopathy (PML)
• known active EBV or CMV viremia
• positive test for hepatitis B surface antigen (HBSAg). Patients with a positive total/IgG hepatitis B core antibody (HBcAb) may participate if hepatitis B virus (HBV) DNA is undetectable at screening, if they agree to take entecavir or tenofovir, and undergo periodic DNA testing
• positive hepatitis C virus (HCV) antibody, unless a negative polymerase chain reaction (PCR) for HCV is documented
• positive test for HIV. 10. Administration of a live, attenuated vaccine within 4 weeks before first mosunetuzumab dose or anticipation that such a live, attenuated vaccine will be required during the study. 11. Current or past history of CNS disease, including stroke, epilepsy, or CNS vasculitis, or an advanced neurodegenerative disease; with the exception of: stroke >2 years before registration without any residual neurologic deficits and no subsequent transient ischemic attacks; history of epilepsy with no seizures for >2 years and not using any antiepileptic therapy; well-controlled Parkinson's disease (with no need for a significant medication adjustment for > 6 months). 12. History of other malignancy that could affect compliance with the protocol or interpretation of results; patients with a curatively treated skin cancer, in situ cervical cancer, or another malignancy treated curatively with a documented remission >2 years before registration are eligible. 13. Known active bacterial, viral, fungal, mycobacterial, parasitic, or other infection (excluding fungal infections of nail beds) at study enrollment or any major episode of infection requiring treatment with IV antibiotics or hospitalization within 4 weeks before the first dose of mosunetuzumab. 14. Clinically significant liver disease, including viral or other hepatitis, current alcohol abuse, or cirrhosis. 15. Any major surgery within 4 weeks before the first dose of mosunetuzumab, other than lymph node biopsy for diagnosis. 16. Evidence of other significant or uncontrolled medical or psychiatric conditions that could affect compliance with the protocol. 17. Any of the following abnormal laboratory values within 14 days prior to first dose of mosunetuzumab:
• AST or ALT >3x ULN
• total bilirubin >2 x ULN (unless due to Gilbert syndrome with indirect hyperbilirubinemia only)
• INR>1.5 x ULN without anticoagulation
• PTT or APTT >1.5x ULN in the absence of lupus anticoagulant. 18. Any radiation therapy within 2 weeks prior to first dose of mosunetuzumab. 19. Pregnancy, breast-feeding, or prisoner status. Women of childbearing potential must have a negative pregnancy test within 2 weeks before first dose of mosunetuzumab, and must undergo repeat pregnancy testing during each cycle of lenalidomide therapy (see Inclusion Criterion 11).

KEY Inclusion Criteria:

1. Previously untreated participants for lymphoma with documented cluster of differentiation 20+ (CD20+) DLBCL, as described in the protocol OR relapsed or refractory DLBCL (Part 1A only) 2. Measurable disease with at least one nodal lesion or at least one extranodal lesion, as described in the protocol 3. Eastern Cooperative Oncology Group (ECOG) performance status ≤2 4. Life expectancy ≥ 12 months 5. International Prognostic Index (IPI) of 3 to 5 (part 1 only) and ≥2 (part 2) for untreated DLBCL only; 6. Adequate hematologic and organ function, as defined in the protocol.

KEY Exclusion Criteria:

1. Primary central nervous system (CNS) lymphoma or known involvement by non-primary CNS NHL and history or current relevant CNS pathology 2. Another active malignancy, significant active disease or medical condition, as described in the protocol 3. Peripheral neuropathy Grade ≥3 4. Treatment with any systemic anti-lymphoma therapy, except for participants with relapsed/refractory (R/R) DLBCL and participants with DLBCL transformed from an indolent follicular lymphoma after treatment with systemic anti-lymphoma therapy. 5. Any other therapy or investigational treatment within 28 days or 5 half-lives of the drug, whichever is shorter, prior to the start of study treatment 6. Recent major surgery, prior organ transplantation, or standard radiotherapy, as described in the protocol 7. Allergy/hypersensitivity to study drugs, as described in the protocol 8. Infections such as any active infection (bacterial, viral, fungal, mycobacterial, parasitic or other), active Coronavirus disease (COVID-19) infection, uncontrolled infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV), Cytomegalovirus (CMV) infection, as described in the protocol.Note: Other protocol-defined Inclusion/ Exclusion criteria apply

Inclusion Criteria:

1. Patient with newly diagnosed, untreated histology-proven PTCL based on local pathology review who is eligible for receiving, Belinostat, Pralatrexate, and CHOP. Pathology material must be available at the site for each patient before enrollment so it can be sent to the Sponsor (or designee) for confirmation. The following subtypes, as defined by the updated World Health Organization (WHO) classification, may be included. This information should be available for eligibility: 1. Pathology subtype:
• Peripheral T-cell lymphoma, not otherwise specified
• Angioimmunoblastic T-cell lymphoma
• Anaplastic lymphoma kinase (ALK)- negative anaplastic large-cell lymphoma (ALCL)
• Follicular T cell lymphoma
• Others: Extra-nodal natural killer/T-cell lymphoma, nasal type; enteropathy-associated T-cell lymphoma; hepatosplenic T-cell lymphoma; and subcutaneous panniculitis-like T-cell lymphoma 2. CD30 expression 3. TFH phenotype 2. Patient has at least 1 site of measurable disease according to Response Evaluation Criteria in Lymphoma (RECIL) 2017 criteria as assessed by the local Investigator (Appendix 3) 3. Patient has an Eastern Cooperative Oncology Group performance status ≤2 4. For Part 1 (Dose Finding) - Patient has adequate hematological, hepatic, and renal function as defined by: a. Absolute neutrophil count ≥1.5×109
• L b. Platelet count ≥100×109
• L c. Total bilirubin ≤1.5 mg/dL d. Aspartate aminotransferase (AST)/serum glutamic-oxaloacetic transaminase (SGOT), alanine aminotransferase (ALT)/serum glutamic-pyruvic transaminase (SGPT) ≤3×the upper limit of normal (ULN; AST/ALT ≤5×ULN if documented hepatic involvement with lymphoma) e. Serum creatinine ≤2.0×ULN or calculated creatinine clearance of ≥60 mL/min 5. Part 2 (Efficacy and Safety) - disease related hypoplasia, hepatological or renal dysfunction can be included if any of the treatment groups can be administered based on package insert recommendation with the following restrictions: 1. Absolute neutrophil count ≥1.0×109/L or >= ≥1.5×109/L if bone marrow involvement 2. Platelet count ≥100×109
• L or ≥75×109
• L if bone marrow involvement 3. Total bilirubin ≤1.5 mg/dL 4. Aspartate aminotransferase (AST)/serum glutamic-oxaloacetic transaminase (SGOT), alanine aminotransferase (ALT)/serum glutamic-pyruvic transaminase (SGPT) ≤3×the upper limit of normal (ULN; AST/ALT ≤5×ULN if documented hepatic involvement with lymphoma) 5. Serum creatinine ≤2.0×ULN 6. Calculated creatinine clearance of ≥60 mL/min 6. UGT1A1 genotype has been characterized (see Belinostat dose modifications if abnormal). 7. A decision whether to use prophylactic growth factor for cycle 1 or not has been made 8. Patient must be willing and capable of giving written informed consent and must be able to adhere to dosing and visit schedules and meet all study requirements 9. Patient (male/female) is at least 18 years of age at the time of informed consent 10. Patient is willing to practice 2 forms of contraception, one of which must be a barrier method, from study entry until at least 30 days after the last dose of study treatment 11. Females of childbearing potential must have a negative urine pregnancy test within 4 weeks prior to the first day of study treatment. Females who are postmenopausal for at least 1 year (defined as more than 12 months since last menses) or are surgically sterilized do not require this test

Exclusion Criteria:

1. Patients with a diagnosis of: 1. Precursor T-cell lymphoma or leukemia 2. Adult T-cell lymphoma/leukemia 3. T-cell prolymphocytic leukemia 4. T-cell large granular lymphocytic leukemia 5. Primary cutaneous type ALCL 6. Cutaneous T-cell lymphoma (mycosis fungoides/Sezary syndrome) 7. ALCL except if Brentuximab Vendotin cannot be utilized 2. Patients taking drugs which are potent UGT1A1 inhibitors must discontinue one week before randomization; drug can be resumed if the treatment doesn't include belinostat 3. Patient with an active concurrent malignancy/life-threatening disease with the exception of non melanoma skin tumors and in situ cervical cancer if they have received treatment resulting in complete resolution of the cancer and currently have no clinical, radiologic, or laboratory evidence of active or recurrent disease. If there is a history of prior malignancies/life-threatening diseases, the patient must be disease free for at least 5 years 4. Prior histone deacetylase (HDAC) inhibitor or pralatrexate therapy 5. Any known cardiac abnormalities such as baseline prolongation of QT/corrected QT (QTc) interval (ie,demonstration of a QTc interval >450 msec); long QT syndrome; myocardial infarction within 6 months prior to starting study; history of significant cardiovascular disease; the required use of a concomitant medication that may cause Torsades de Pointes 6. Patient with uncontrolled hypertension 7. Patients with a known HIV-positive diagnosis, hepatitis B virus or hepatitis C virus diagnosis with detectable viral load or immunological evidence of chronic active disease 8. Patient with central nervous system metastasis 9. Patient with an active uncontrolled infection, underlying medical condition, laboratory abnormality, or other serious illness that would impair the ability of the patient to receive protocol treatment 10. Patient who has used any investigational drugs, biologics, or devices within 28 days prior to study treatment or plans to use any of these during the course of the study 11. Patient with a known history of drug or alcohol abuse 12. Pregnant or breastfeeding women

Inclusion Criteria:

• History or status of a histologically-confirmed hematological malignancy that is expected to express CD19 and CD20; relapse after or failure to respond to at least one prior treatment regimen; no available treatment options that are expected to prolong survival (Part I and II); relapsed after or failed to respond to only one prior systemic treatment regimen (Part III)
• Must have at least one measurable target lesion (>/= 1.5 cm) in its largest dimension by computed tomography scan
• Able and willing to provide a fresh biopsy from a safely accessible site, per Investigator's determination, providing the participant has more than one measurable target lesion
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, or
• Life expectancy of >/= 12 weeks
• Adverse events from prior anti-cancer therapy must have resolved to Grade
• Adequate liver, hematological, and renal function
• Negative test results for acute or chronic hepatitis B virus infection
• Negative test results for hepatitis C virus and HIV
• The contraception and abstinence requirements are intended to prevent exposure of an embryo to the study treatment. The reliability of sexual abstinence for male and/or female enrollment eligibility needs to be evaluated in relation to the duration of the clinical study and the preferred and usual lifestyle of the participant. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or post-ovulation methods) and withdrawal are not acceptable methods of preventing drug exposure
• Female participants: A female participant is eligible to participate if she is not pregnant and not breastfeeding, and if at least one of the following applies: women of non-childbearing potential (WONCBP); women of child bearing potential (WOCBP) who agree to remain abstinent or use two highly effective contraceptive methods with a failure rate of <1% per year during the treatment period and for at least 18 months after obinutuzumab or 3.5 months after the last dose of englumafusp alfa, 2 months after last dose of glofitamab, or 3 months after the last dose of tocilizumab, whichever is longer. Examples of contraceptive methods with a failure rate of < 1% per year include bilateral tubal occlusion/ ligation, male sexual partner who is sterilized, established proper use of hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices and copper intrauterine devices. Hormonal contraceptive methods must be supplemented by a barrier method; have a negative pregnancy test (blood) within the 7 days prior to the first study treatment administration
• Male participants: During the treatment period and for at least 3 months after obinutuzumab, or 3.5 months after the last dose of englumafusp alfa, 2 months after the last dose of glofitamab, or 2 months after the last dose of tocilizumab whichever is longer, agreement to: Remain abstinent or use contraceptive measures such as a condom plus an additional contraceptive method that together result in a failure rate of < 1% per year, with a partner who is a women of childbearing potential. With pregnant female partner, remain abstinent or use contraceptive measures such as a condom to avoid exposing the embryo; refrain from donating sperm during this same period

Exclusion Criteria:

• Circulating lymphoma cells, defined by out of range (high) absolute lymphocyte count (ALC) or the presence of abnormal cells in the peripheral blood signifying circulating lymphoma cells (for some participants in Part III, ALC only)
• Participants with acute bacterial, viral, or fungal infection at baseline, confirmed by a positive blood culture within 72 hours prior to obinutuzumab infusion or by clinical judgment in the absence of a positive blood culture
• Participants with known active infection, or reactivation of a latent infection, whether bacterial, viral fungal, mycobacterial, or other pathogens (excluding fungal infections of nail beds) or any major episode of infection requiring hospitalization or treatment with IV antibiotics
• Pregnant or breast-feeding or intending to become pregnant during the study
• Prior treatment with systemic immunotherapeutic agents, including, but not limited to, radio-immunoconjugates, antibody-drug conjugates, immune/cytokines or monoclonal antibodies within 4 weeks or five half-lives of the drug, whichever is shorter, before obinutuzumab infusion
• History of treatment-emergent immune-related AEs associated with prior immunotherapeutic agents and auto-immune disease
• Treatment with standard radiotherapy, any chemotherapeutic agent, or treatment with any other investigational or approved anti-cancer agent within 4 weeks or 5 half-lives of the drug, whichever is shorter, prior to obinutuzumab infusion
• Prior solid organ transplantation
• Prior allogeneic stem cell transplant (SCT) and prior chimeric antigen receptor
• T-cell therapy
• Autologous SCT within 100 days prior to obinutuzumab infusion
• History of severe allergic or anaphylactic reactions to monoclonal antibody therapy and confirmed progressive multifocal leukoencephalopathy
• Current or past history of central nervous system (CNS) lymphoma and CNS disease
• Evidence of significant, uncontrolled concomitant diseases that could affect compliance with the protocol or interpretation of results, including diabetes mellitus, history of relevant pulmonary disorders and known autoimmune diseases
• Major surgery or significant traumatic injury < 28 days prior to the Gpt infusion or anticipation of the need for major surgery during study treatment
• Participants with another invasive malignancy in the last 2 years
• Significant cardiovascular disease
• Administration of a live, attenuated vaccine within 4 weeks before Gpt infusion or anticipation that such a live attenuated vaccine will be required during the study
• Received systemic immunosuppressive medications (including but not limited to cyclohosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor agents) within two weeks prior to Gpt, with the exception of corticosteroid treatment <=25 mg/day of prednisone or equivalent, however there must be documentation that the participant was on a stable dose of at least a 2-week duration prior to Gpt infusion. Inhaled and topical steroids are permitted

Inclusion Criteria:

• Participants must have histologically or cytologically confirmed diffuse large B-cell lymphoma (DLBCL), Ann Arbor Stage IIX (bulky), III or IV. Participants with DLBCL transformed from follicular lymphoma (FL) or marginal zone lymphoma (MZL, including mucosa-associated lymphoid tissue [MALT] lymphomas), lymphoplasmacytic lymphoma (LPL), or nodular lymphocyte-predominant Hodgkin Lymphoma (NLPHL) are eligible. Participants with Grade IIIB follicular lymphoma (FL) or high-grade B-cell lymphomas with MYC and BCL2 and/or BCL6 rearrangements are also eligible. Participants with DLBCL that arose from prior CLL (Richter's transformation) are not eligible.
• As defined by the World Health Organization (WHO), eligible lymphoma subtypes include the following:
• DLBCL, not otherwise specified (NOS)
• DLBCL, germinal-center B-cell type (GCB)
• DLBCL, activated B-cell type (ABC)
• T-cell histiocyte-rich B-cell lymphomas (THRBCL)
• Primary cutaneous DLBCL, leg type
• Intravascular large B cell lymphoma
• EBV+ DLBCL, NOS
• DLBCL associated with chronic inflammation
• HHV8+ DLBCL, NOS
• High-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements
• High grade B-cell lymphoma, NOS
• Follicular lymphoma grade 3b
• Participants must have staging imaging performed within 28 days prior to registration, as follows. Positron emission tomography (PET)-computed tomography (CT) baseline scans are strongly preferred; diagnostic quality magnetic resonance imaging (MRI), contrast-enhanced CT, or contrast-enhanced MRI scans are also acceptable if PET-CT is not feasible at baseline. Note: PET-CT will be required at end of treatment (EOT) and progression for response assessment. Participants must have measurable disease (at least one lesion with longest diameter ≥ 1.5 cm). All measurable lesions (longest diameter >= 1.5 cm) must be assessed within 28 days prior to registration. Tests to assess non-measurable disease must be performed within 42 days prior to registration.
• Participants with known human immunodeficiency virus (HIV)-infection are eligible providing they are on effective anti-retroviral therapy and have undetectable viral load at their most recent viral load test (must be within 26 weeks prior to registration). Participants with known HIV must have a CD4 count checked within 28 days prior to registration, but may proceed with therapy regardless of CD4 count.
• All participants must be screened for chronic hepatitis B virus (HBV) within 28 days prior to registration. Participants with known HBV infection (positive serology) must also have a HBV viral load performed within 28 days prior to registration, and participants must have an undetectable HBV viral load on suppressive therapy within 28 days prior to registration. Participants found to be HBV carriers during screening are eligible and must receive standard of care prophylaxis. Participants with active hepatitis B (HBV viral load > 500 IU/mL) within 28 days prior to registration are not eligible
• Participants with a known history of hepatitis C virus (HCV) infection must have an undetectable HCV viral load within in 28 days prior to registration
• Participants must not have known lymphomatous involvement of the central nervous system (CNS)
• Participants must not have active inflammatory bowel disease (such as, Crohn's disease, ulcerative colitis), celiac disease (i.e., sprue), prior gastrectomy or upper bowel removal, or any other gastrointestinal disorder or defect that would interfere with the absorption, distribution, metabolism, or excretion of the study drug and/or predispose the subject to an increased risk of gastrointestinal toxicity
• Participants must not have a history of acute leukemia having been treated with intensive induction therapy. 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
• Participants must not have received any prior cytotoxic chemotherapy or rituximab for treatment of the newly diagnosed DLBCL except for the pre-phase treatment (within specified dose range) that may have either started before or may start after registration to S1918. Inhaled, nasal, and topical steroid use is allowed. Prior cytotoxic chemotherapy and/or antibody therapy for an indolent lymphoma prior to transformation is allowed. Up to 4 doses of intrathecal (IT) chemotherapy administered for central nervous system (CNS) prophylaxis is allowed in addition to protocol therapy. High-dose intravenous methotrexate is not allowed.
• Participants must not have received more than a cumulative of dose 250 mg/m^2 of prior doxorubicin (or equivalent dose of another anthracycline, such as epirubicin) therapy (at any time prior to registration).
• Participants must not currently be receiving any other investigational agents
• Participant must not have a history of allergic reactions attributed to azacitidine, mannitol, or other hypomethylating agents
• Participants must be age ≥ 75
• Participants must have a Zubrod performance status of 0-2
• Participants must have adequate renal function, as demonstrated by a creatinine clearance, calculated by the Cockcroft and Gault formula, of >= 30 ml/min that was obtained within 28 days prior to registration
• Aspartate aminotransferase (AST) =< 2.5 x institutional upper limit of normal (IULN), alanine aminotransferase (ALT) =< 2.5 x IULN (within 28 days prior to registration)
• Total bilirubin =< 2 x institutional upper limit of normal (IULN), unless due to Gilbert's disease, hemolysis, or lymphomatous involvement of liver (within 28 days prior to registration). Note: If total bilirubin is elevated, and direct bilirubin is subsequently performed (within 28 days prior to registration) and resulted to be =< 2 x IULN, the participant will be considered eligible
• Absolute neutrophil count (ANC) >= 1000/mcL (within 28 days prior to registration)
• Platelets >= 75,000/mcL (within 28 days prior to registration)
• Hemoglobin (Hgb) >= 8 g/ dL (within 28 days prior to registration)
• If there is a documented lymphomatous involvement of the bone marrow, bone marrow function within 28 days prior to registration, as evidenced by:
• ANC >= 500/mcL
• Platelets >= 50,000/mcL
• Hemoglobin (Hgb) >= 8 g/ dL
• Participants must have a left ventricular ejection (LVEF) fraction >= 45% as measured by echocardiogram or radionuclide (multigated acquisition scan [MUGA]) ventriculography within 56 days prior to registration
• For the duration of the study treatment period and for at least 4 months following the last dose of study drug, male participants must agree to use effective contraceptive methods during sexual contact with a female of childbearing potential (FCBP) and must agree to refrain from semen or sperm donation during the same timeframe. Effective contraceptive methods include a history of vasectomy, use of hormonal contraception or an intrauterine device (IUD) by the female partner, or use of condoms
• A FCBP is a sexually mature woman who: 1) has not undergone a hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 24 consecutive months (i.e., has had menses at any time in the preceding 24 consecutive months)
• Participants must not have active infection (systemic fungal, bacterial, or viral infection) that is not controlled (defined as ongoing signs/symptoms related the infection without improvement despite appropriate antibiotics, antiviral therapy, and/or other treatment)
• Participants must not have active cardiac disease within 26 weeks prior to registration, including: symptomatic congestive heart failure (New York Heart Association [NYHA] class 4), unstable angina pectoris, hemodynamically unstable cardiac arrhythmia, or myocardial infarction
• Participants must not have >= grade 2 neuropathy, by Common Terminology Criteria for Adverse Events (CTCAE) version (v.) 5.0, within 28 days prior to registration
• Participants must not have any other known uncontrolled intercurrent illness including, but not limited to ongoing psychiatric illness/social situations that would limit compliance with study requirements
• Participants must not have a concurrent primary malignancy undergoing active therapy. Exceptions: participants may have non-melanomatous skin cancers requiring only surgical intervention. Participants may have a history of early stage breast cancer or prostate cancer in remission after surgical and/or radiation therapy on adjuvant hormonal therapy only

Inclusion Criteria:

• Life expectancy at least 12 weeks
• Histologically-confirmed MCL, with documentation of either overexpression of cyclin D1 or the presence of t(11:14)
• Relapsed (disease progression after the last treatment regimen) or refractory (failure to achieve a partial or complete response from the last treatment regimen) disease
• At least 1 line of prior systemic therapy including a BTK inhibitor and additional systemic therapy option
• Confirmed availability of tumor tissue, unless deemed unsafe per investigator assessment
• At least one bi-dimensionally measurable (defined as at least 1.5 cm) nodal lesion, or one bi-dimensionally measurable (at least 1 cm) extranodal lesion, as measured on CT scan
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2
• Negative HIV test at screening
• Adequate hematological function

Exclusion Criteria:

• Pregnancy or breastfeeding, or intention of becoming pregnant during the study or within 3 months after the final dose of tocilizumab, 2 months after the final dose of glofitamab, whichever is longer
• Leukemic, non-nodal MCL
• History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies (or recombinant antibody-related fusion proteins) or known sensitivity or allergy to murine products
• Contraindication to obinutuzumab or rituximab, and either bendamustine or lenalidomide
• Prior treatment with glofitamab or other bispecific antibodies targeting both CD20 and CD3
• Prior treatment with CAR-T cell therapy
• Treatment with systemic therapy or BTK inhibitors, or any investigational agent for the purposes of treating cancer within 2 weeks or 5 half-lives (whichever is shorter) prior to first study treatment
• Primary or secondary CNS lymphoma at the time of recruitment or history of CNS lymphoma
• Current or history of CNS disease, such as stroke, epilepisy, CNS vasculitis, or neurodegenerative disease
• History of other malignancy that could affect compliance with the protocol or interpretation of results
• Significant or extensive cardiovascular disease
• Known active bacterial, viral, fungal, mycobacterial, parasitic, or other infection at study enrollment or any major episode of infection within 4 weeks prior to the first study treatment
• Suspected or latent tuberculosis
• Positive test for hepatitis B virus (HBV) or hepatitis C virus (HCV)
• Known or suspected chronic active Epstein-Barr viral infection (EBV)
• Known or suspected history of hemophagocytic lymphohistiocytosis (HLH)
• Known history of progressive multifocal leukoencephalopathy (PML)
• Adverse events from prior anti-cancer therapy that have not resolved to Grade 1 or better
• Administration of a live, attenuated vaccine within 4 weeks before first study treatment administration or anticipation that such a live, attenuated vaccine will be required during the study
• Prior solid organ transplantation or allogenic stem cell transplant
• Eligibility for stem cell transplantation (SCT)
• Active autoimmune disease requiring treatment
• Prior treatment with systemic immunosuppressive medications within 2 weeks or five half-lives (whichever is shorter) prior to the first dose of study treatment
• Corticosteroid therapy within 2 weeks prior to first dose of study treatment
• Recent major surgery (within 4 weeks before the first study treatment) other than for diagnosis
• Clinically significant history of cirrhotic liver disease

Key Inclusion Criteria:

1. LBCL per WHO 2017 including diffuse large B-cell lymphoma, high-grade B-cell lymphoma, and primary mediastinal B-cell lymphoma histologically confirmed by pathology report. 2. Participant has completed a full course of standard first line therapy (e.g., R-CHOP, dose-adjusted EPOCH-R, Pola-R-CHP) as intended. Participants cannot have received additional lines of therapy. 3. Participant achieved CR, or PR suitable for observation at the end of first line therapy based on PET/CT evaluation 4. Foresight CLARITY™ IUO MRD test, powered by PhasED-Seq™, is positive. 5. Adult participants ≥18 years of age. 6. Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1. 7. Adequate hematological, renal, hepatic, pulmonary, and cardiac function 8. Non-hematologic toxicities related to prior therapy must be recovered to baseline or grade ≤1.

Key Exclusion Criteria:

1. LBCL with history of central nervous system involvement, transformed from other malignancy (e.g., transformed follicular lymphoma or marginal zone lymphoma, Richter's transformation), or T-cell/histiocyte rich LBCL. 2. Prior treatment with anti-CD19 targeted therapies. 3. Anti-cancer treatment, including radiation, after end of treatment PET/CT and/or MRD testing is performed. 4. Active and clinically significant autoimmune disease. 5. Active systemic bacterial, fungal, or viral infections requiring systemic treatment (e.g., HIV). 6. History of another primary malignancy or bone marrow disorder (e.g., myelofibrosis, smoldering multiple myeloma) within 3 years prior to enrollment.