A Study Evaluating the Safety, Pharmacokinetics, and Efficacy of Mosunetuzumab or Glofitamab in Combination With CC-220 and/or CC-99282 in Participants With B-Cell Non-Hodgkin Lymphoma

Inclusion Criteria:

• Age >/= 18 years

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0, 1, or 2

• History of one of the following histologically documented hematologic malignanciesthat are expected to express the CD20 antigen: In the Dose Escalation phase,participants must have relapsed after or failed to respond to at least two priorlines of systemic therapy. In the Dose Expansion phase, participants with FL Grades 1-3a must have relapsed after or failed to respond to at least one prior line ofsystemic therapy and must require systemic therapy. Participants withDLBCL/transformed FL must have relapsed after or failed to respond to at least oneprior systemic treatment regimen.

• Participants with DLBCL/transformed FL who have received only one prior line oftherapy must: Not be considered a candidate for autologous stem cell transplantation (ASCT) due to age, performance status, comorbidities and/or insufficient response toprior treatment, or have refused ASCT; or be ineligible for or unable to receivechimeric antigen receptor T-cell (CAR-T) therapy due to reasons defined by theprotocol

• Fluorodeoxyglucose-avid lymphoma (i.e. PET-positive lymphoma)

• At least one bi-dimensionally measurable nodal lesion (> 1.5 cm in its largestdimension by diagnostic quality CT or PET/CT scan), or at least one bi-dimensionallymeasurable extranodal lesion (> 1.0 cm in its largest dimension by diagnosticquality CT or PET/CT scan)

• Availability of a representative tumor specimen and the corresponding pathologyreport for confirmation of the diagnosis of NHL

• A fresh pretreatment biopsy during screening period, excisional or incisional, ispreferred

• Adequate hematologic function without growth factors or blood product transfusionwithin 14 days of first dose of study drug administration

• Normal laboratory values

• All participants and health care providers will be trained and counseled onpregnancy prevention. For female participants of childbearing potential: agreementto remain abstinent (refrain from heterosexual intercourse) or use contraceptionduring the treatment period and for 3 months after the final dose of mosunetuzumab,at least 18 months after pre-treatment with obinutuzumab or 2 months after the lastdose of glofitamab, 28 days after the last dose of CC-220, 28 days after the lastdose of CC-99282, 3 months after the last dose of tocilizumab (if applicable),whichever is longer

• For male participants: agreement to remain abstinent (refrain from heterosexualintercourse) or use a condom, and agree to refrain from donating sperm during thetreatment period and for at least 3 months after pre-treatment with obinutuzumab or 2 months after the last dose of glofitamab, 28 days after the last dose of CC-220, 28 days after the last dose of CC- 99282, 2 months after the final dose oftocilizumab (if applicable), whichever is longer

Exclusion Criteria:

• Pregnancy or breastfeeding, or intention of becoming pregnant during the study (female participants of childbearing potential must have a negative serum pregancytest result within 14 days prior to initiation of the study treatment) or within 3months after the final dose of mosunetuzumab, at least 3 months after pre-treatmentwith obinutuzumab or 2 months after the last dose of glofitamab, whichever islonger, 28 days after the last dose of CC-220, 28 days after the last dose ofCC-9282, 3 months after the final dose of tocilizumab, whichever is longer

• Participant has received prior therapy with cereblon (CRBN)-modulating drug (e.g.,lenalidomide, avadomide/CC-122, pomalidomide) </= 4 weeks prior to starting CC-220and/or CC-99282

• Inability to swallow pills, or persistent diarrhea or malabsorption >= Grade 2National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE), despite medical management

• QTc interval of > 470 ms

• The following treatments prior to study entry: mosunetuzumab, glofitamab, or otherCD20/CD3-directed bispecific antibodies; allogenic stem cell therapy (SCT); solidorgan transplantation

• Treatments (investigational or approved) within the following time periods prior toinitiation/first dose of study treatment: radiotherapy within 2 weeks; autologousSCT within 100 days; chimeric antigen receptor (CAR) T-cell therapy within 30 days;prior anti-lymphoma treatment with monoclonal antibodies or antibody-drug conjugateswithin 4 weeks; use of radioimmunoconjugates within 12 weeks; systemicimmunosuppressive medications within 2 weeks; any other anti-cancer therapy, whetherinvestigational or approved, including but not limited to chemotherapy, within 4weeks or 5 half-lives of the drug, whichever is shorter

• Live, attenuated vaccine within 4 weeks before first dose of study treatment, or inwhom it is anticipated that such a live attenuated vaccine will be required duringthe study period or within 5 months after the final dose of study treatment

• Current or past history of central nervous system (CNS) lymphoma or leptomeningealinfiltration

• History of severe allergic or anaphylactic reactions to humanized or murinemonoclonal antibody therapy (or recombinant antibody-related fusion proteins)

• History of autoimmune disease, including but not limited to myocarditis,pneumonitis, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupuserythematosus, rheumatoid arthritis, inflammatory bowel disease, vascular thrombosisassociated with antiphospholipid syndrome, granulomatosis with polyangiitis,Sjögren's syndrome, Guillain-Barré syndrome, multiple sclerosis, vasculitis, orglomerulonephritis

• Major surgery or significant traumatic injury < 28 days prior to enrollment (excluding biopsies) or anticipation of the need for major surgery during studytreatment

• Clinically significant toxicities from prior treatment have not resolved to Grade </= 1 (per US national cancer institute (NCI) common terminology criteria foradverse events (CTCAE) v5.0) prior to the first study drug administration withexceptions defined by the protocol

• Evidence of any significant, concomitant disease (e.g. cardiovascular, pulmonary,liver, CVA or stroke, ILD, PML, infection, HLH etc) that could affect compliancewith the protocol or interpretation of results

• For participants enrolled into glofitamab cohort: documented refractoriness to anobinutuzumab monotherapy-containing regimen (defined as disease that did not achieveresponse (PR or CR) or progressed within 6 months of the last dose of anobinutuzumab-containing regimen)