This is an open-label, multicenter, non-randomized extension study. Participants receiving atezolizumab monotherapy or atezolizumab combined with other agent(s) or comparator agent(s) in a Genentech or Roche-sponsored study (the parent study) and who continue to receive study treatment at the time of the parent-study closure are eligible for continued treatment in the extension study. Dosing regimen for a given participant and indication will be according to the respective parent study. Study treatment in the extension study can continue until disease progression or beyond if the participant continues to derive clinical benefit in the judgment of the investigator and if allowed by the parent study or local prescribing information, death, withdrawal of study consent, unacceptable toxicity, pregnancy, participant non-compliance, or study termination by the Sponsor, whichever occurs first.