The main inclusion criteria include but are not limited to the following: - Has a histological or cytological diagnosis of locally advanced, unresected Stage II (node-positive) to III non-small cell lung cancer (NSCLC) with predominantly nonsquamous histology. - Has completed definitive platinum-based concurrent chemoradiotherapy (CCRT) prior to enrollment, without disease progression. - Has provided a tumor tissue sample for central laboratory testing of Kirsten rat sarcoma G12C (KRAS G12C) status, programmed cell death ligand 1 (PD-L1) status, and biomarker research. - Tumor tissue sample has a demonstrated presence of KRAS G12C mutation and an evaluable PD-L1 status result. - If human immunodeficiency virus (HIV)-infected, has well-controlled HIV on antiretroviral therapy (ART). - If hepatitis B surface antigen (HBsAg)-positive, has undetectable hepatitis B virus (HBV) viral load and has received HBV antiviral therapy. - If has a history of hepatitis C virus (HCV) infection, has undetectable HCV viral load. - Has a body weight ≥35 kg.

The main exclusion criteria include but are not limited to the following: - Has a diagnosis of small cell lung cancer or mixed tumors with small cell elements. - Has a gastrointestinal disorder affecting absorption or is unable to swallow orally administered medication. - Has active inflammatory bowel disease requiring immunosuppressive medication or previous clear history of inflammatory bowel disease. - Has uncontrolled, significant cardiovascular disease or cerebrovascular disease. - Is HIV-infected with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease. - Has received prior treatment (other than definitive CCRT) for NSCLC. - Has a known additional malignancy that is progressing or has required active treatment within the past 3 years. - Has an active autoimmune disease that has required systemic treatment in the past 2 years. - Has a history of, or has current, (noninfectious) pneumonitis/interstitial lung disease that required/requires steroids. - Has an active infection requiring systemic therapy. - Has a history of stem cell/solid organ transplant. - Has not adequately recovered from major surgery or has ongoing surgical complications.