A Study to Evaluate the Safety, Tolerability, Pharmacokinetics (PK), Pharmacodynamics (PD), and Preliminary Activity of Tiragolumab in Participants With Relapsed or Refractory Multiple Myeloma or With Relapsed or Refractory B-cell Non-Hodgkin Lymphoma

Administered by IV infusion at a fixed dose of 600 mg on Day 1 of each 21-day cycle (Q3W)

Administered by SC injection 1800 mg/30,000 U rHuPH20 weekly for a total of 6 doses, then every 3 weeks for a total of 16 doses (first dose given at Week 7), then every 4 weeks from Week 55 onward until disease progression

Administered for a total of 8 doses. Rituximab will be administered by IV infusion for the first dose at a dose of 375 mg/m\^2. After administration of at least one full infusion of IV rituximab, the SC formulation of rituximab (rituximab and rHuPH20) may be used for the remaining doses per institutional guidelines. SC rituximab will be administered at a dose of 1400 mg rituximab/23400 U rHuPH20 once weekly (QW).

Administered by IV infusion at a fixed dose of 1200 mg Q3W