A Study of Glofitamab in Combination With Rituximab or Obinutuzumab Plus Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone (CHOP), or Polatuzumab Vedotin Plus Rituximab, Cyclophosphamide, Doxorubicin, and Prednisone (CHP) in Participants With Non-Hodgkin Lymphomas or With DLBCL

This is a phase 1B, multi-center, dose-finding study of glofitamab administered in combination with obinutuzumab (Gazyva; \[G\]), rituximab (R) and standard doses of CHOP (G/R-CHOP or R-CHOP) in participants with r/r NHL and G/R CHOP or Pola-R-CHP in participants with untreated diffuse large B-cell lymphoma (DLBCL). Evaluating the safety, preliminary activity, pharmacokinetic (PK), and pharmacodynamic effects of this combination will be the main objectives of this study. The study is divided in two parts: * Part I: Dose finding in participants with r/r NHL; test use of G vs R in Cycle 1 * Part II: Dose Expansion. The maximum tolerated dose or optimal biological dose (MTD or OBD) will be further assessed in participants with untreated DLBCL (\>18 years of age with an age-adjusted International Prognostic Index (IPI) of 2-5). Glofitamab will be studied in combination with R-CHOP and Pola-R-CHP.