A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Efficacy of RO7443904 in Combination With Glofitamab in Participants With Relapsed/Refractory B-Cell Non-Hodgkin's Lymphoma

Inclusion Criteria:

* Body weight \>=40 kg
* Histologically confirmed hematological malignancy that is expected to express CD19 and CD20 and with clinical evidence of treatment need; 2) relapse after or failure to respond to at least two prior treatment regimens; and 3) no other available treatment options that are known to provide clinical benefit
* Must have at least one measurable target lesion (\>=1.5 cm) in its largest dimension by computed tomography (CT) scan
* Able and willing to provide a fresh tumor biopsy from a safely accessible site, per Investigator's determination
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
* Life expectancy of \>=12 weeks
* Adequate liver, hematological and renal function
* Negative serologic or polymerase chain reaction (PCR) test results for acute or chronic hepatitis B virus (HBV) infection
* Negative test results for hepatitis C virus (HCV) and HIV
* A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: 1) Women of non-childbearing potential 2) Women of childbearing potential (WOCBP), who, agree to remain abstinent (refrain from heterosexual intercourse) or use of one highly effective contraceptive method during the treatment period and for at least 18 months after obinutuzumab or 5 months after the final dose of RO7443904, 2 months after final dose of glofitamab or 3 months after the final dose of tocilizumab
* Male participants must remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures such as a condom plus an additional contraceptive method with a partner who is a WOCBP during the treatment period and for at least 3 months after obinutuzumab, 5 months after the final dose of RO7443904, 2 months after the final dose of glofitamab or 2 months after the final dose of tocilizumab, whichever is longer

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
* Participants with known acute bacterial, viral, or fungal infection 72 hours prior to glofitamab infusion
* Participants with known active infection or reactivation of a latent infection
* Pregnant, breastfeeding, or intending to become pregnant during the study
* Prior treatment with systemic immunotherapeutic agents
* History of treatment-emergent, immune-related adverse events (AEs) associated with prior immunotherapeutic agents
* Persistent AEs from prior anti-cancer therapy Grade \>=1
* Treatment with standard radiotherapy, any chemotherapeutic agent, or treatment with any other investigational or approved anti-cancer agent
* Prior solid organ transplantation
* Prior allogeneic stem cell transplant (SCT)
* Autologous SCT within 100 days prior to obinutuzumab infusion
* Autoimmune disease in active phase or exacerbation/flare within at least 6 months of enrollment
* History of immune deficiency disease that increases the risk of infection
* History of contraindication and/or severe allergic or anaphylactic reactions to monoclonal antibody therapy and/or prophylactic drugs used for cytokine release syndrome (CRS) and tumor lysis syndrome (TLS)
* History of confirmed progressive multifocal leukoencephalopathy
* Current or past history of central nervous system (CNS) lymphoma or CNS disease
* Evidence of significant, uncontrolled concomitant diseases that could affect compliance with the protocol or interpretation of results
* 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 for reasons other than anticancer therapy within the last 6 months of enrollment with the exception of corticosteroid treatment \<= 25 mg/day prednisone or equivalent
* History of illicit drug or alcohol abuse within 12 months prior to screening, in the Investigator's judgment
* Any other diseases, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that would contraindicate the use of an investigational drug