A Study of Pinatuzumab Vedotin (DCDT2980S) Combined With Rituximab or Polatuzumab Vedotin (DCDS4501A) Combined With Rituximab or Obinutuzumab in Participants With Relapsed or Refractory B-Cell Non-Hodgkin's Lymphoma (NHL)

Inclusion Criteria:

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

- Life expectancy of at least 12 weeks

- History of histologically documented r/r Grades 1 to 3a FL, or r/r DLBCL

- Availability of an archival or freshly biopsied tumor tissue sample must be confirmed
for study enrollment

- Have a clinical indication for treatment as determined by the investigator

- Must have at least one bi-dimensionally measurable lesion (greater than [>] 1.5
centimeters [cm] in its largest dimension by CT scan or Magnetic Resonance Imaging
[MRI])

Exclusion Criteria:

- Prior use of any monoclonal antibody, radio-immuno-conjugate or antibody drug
conjugate within 4 weeks before study start

- Treatment with radiotherapy, chemotherapy, immunotherapy, immunosuppressive therapy,
or any investigational anti-cancer agent within 2 weeks prior study start

- Adverse events except for sensory neuropathy from any previous treatments must be
resolved or stabilized to Grade less than equal to (
- Completion of autologous stem cell transplant (SCT) within 100 days prior study start

- Prior allogeneic SCT

- Eligibility for autologous SCT (participants with r/r DLBCL)

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

- History of other malignancy that could affect compliance with the protocol or
interpretation of results

- Current or past history of central nervous system lymphoma

- Current Grade >1 peripheral neuropathy

- Vaccination with a live vaccine within 28 days prior to treatment