A Study to Evaluate the Efficacy and Safety of Divarasib Compared With Investigator's Choice of Immunotherapy or Observation in Participants With Resected Stage II-III KRAS G12C-Positive Non-Small Cell Lung Cancer (NSCLC)

Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
* Histological or cytological diagnosis of clinical Stage II-IIIB NSCLC of either non-squamous or squamous histology
* Participants must have had complete resection of NSCLC
* Prior treatment with neoadjuvant immune checkpoint inhibitor (pembrolizumab or nivolumab) in combination with histology-based platinum-based doublet chemotherapy
* Participants must be randomized within 12 weeks of their surgery date
* No evidence of disease recurrence or metastatic disease
* Documentation of the presence of a KRAS G12C mutation

Exclusion Criteria:

* Participants who achieve pCR following neoadjuvant treatment
* Prior treatment with a KRAS inhibitor or any other anti-cancer therapy not otherwise specified in the protocol
* Prior treatment with radiation therapy for NSCLC, with the exception of localized symptom-directed radiation prior to surgical resection
* Resolved Grade 3 or greater immune-related AE or unresolved Grade 2 or greater immune-related AE from neoadjuvant immunotherapy
* Active or history of autoimmune disease or immune deficiency
* Significant cardiovascular disease