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