Immunotherapy After Surgery for People Who Have No Remaining Cancer Cells After Standard Treatment for Early-Stage Non-Small Cell Lung Cancer, INSIGHT Trial

Inclusion Criteria: * Participants must have histologically or cytological confirmed diagnosis of clinical stage II-IIIB (excluding clinical N3 disease) non-small cell lung cancer (NSCLC) * Participants must have had a complete (R0) resection of NSCLC (with appropriate lymph node sampling as defined by the National Comprehensive Cancer Network \[NCCN\] guidelines) within 84 days (12 weeks) prior to randomization. Acceptable types of surgical resection are: lobectomy, sleeve resection, bi-lobectomy, or pneumonectomy. Wedge resection is not allowed. * Note the NCCN guidelines: N1 and N2 node resection and mapping is a routine component of lung cancer resections. It is recommended at a minimum one N1 and three N2 stations is sampled or complete lymph node dissection. Formal ipsilateral mediastinal lymph node dissection is indicated for participants undergoing resection for N2 disease * Participants must have a pathologic complete response (pCR) (no viable tumor in the resected specimen or lymph nodes), as determined by local pathology review * Participants must have a PD-L1 status result (e.g. \[\< 1% versus \>= 1% or unknown\]) * Participants must not have known EGFR mutations, or ALK gene fusion * Participants must have received at least two cycles of neoadjuvant platinum-based chemotherapy and anti-PD-1 or anti-PD-L1 therapy. The neoadjuvant treatment must be Food and Drug Administration (FDA) approved and standard of care as listed in NCCN guidelines * Participants must …