Cohort A* (closed): Has an untreated and unresectable or metastatic NSCLC with histologically confirmed (squamous or nonsquamous) KRASG12C mutation and histologically confirmed PD-L1 TPS ≥1%. - Cohort C: Has an untreated and unresectable or metastatic NSCLC with histologically confirmed (non-squamous only) KRASG12C mutation and histologically confirmed PD-L1 TPS < 50% AND previously completed 4 cycles of standard-of-care platinum based induction chemotherapy with pembrolizumab AND experienced stable disease, partial response, or complete response per investigator's assessment after 4 cycles OR if patients received <4 cycles of a platinum-based induction, was stopped early due to intolerable toxicity - Cohort E: Has an untreated and unresectable or metastatic NSCLC with histologically confirmed (non-squamous only) KRASG12C mutation and histologically confirmed PD-L1 TPS < 50% - Presence of measurable disease per RECIST v1.1 Exclusion Criteria: - All Cohorts: Any prior therapy targeting KRASG12C mutation in any setting - Cohorts A & E: Prior systemic therapy for locally advanced or metastatic NSCLC, including chemotherapy, immune checkpoint inhibitor therapy or chemoimmunotherapy (note: prior systemic therapy or chemoradiation given in the adjuvant or neoadjuvant setting are allowed if last dose of prior systemic treatment was >1 year prior to first dose of study treatment) - Cohort C: received maintenance therapy (e.g, pembrolizumab and/or pemetrexed following completion of 4-6 cycles of a platinum-based regimen administered in the first-line setting - Radiation to the lung > 30 Gy within 6 months prior to first dose of study treatment - Active brain metastases