This study aims to evaluate the antitumor activity and safety of JDQ443 single-agent as first-line treatment for participants with locally advanced or metastatic non-small cell lung cancer (NSCLC) whose tumors harbor a KRAS G12C mutation and have a PD-L1 expression \< 1% (cohort A) or a PD-L1 expression ≥ 1% and an STK11 co-mutation (cohort B).