Participants will either be monitored with regular scans or receive the study drug atezolizumab, given by IV infusion or injection every 21 days for up to 1 year. Treatment will continue unless the cancer returns or side effects become too severe. Researchers will compare whether the study drug helps prevent the cancer from coming back compared with monitoring alone.

People that have early-stage non-small cell lung cancer that has been surgically removed

Participants may be able to join if they are adults with stage IA3 or IB non-small cell lung cancer who have had the tumor completely removed with surgery. They must have had testing of nearby lymph nodes and cannot have certain genetic changes, such as EGFR or ALK alterations. Participants cannot have received previous drug treatment for their current lung cancer and cannot have serious uncontrolled illnesses or infections.

This study is comparing the usual approach of monitoring patients after lung cancer surgery with treatment using atezolizumab. Researchers want to learn if giving atezolizumab after surgery can better prevent the cancer from returning compared with observation alone.