The goal of this study is to evaluate intismeran autogene plus pembrolizumab versus placebo plus pembrolizumab for the adjuvant treatment of margin negative, completely resected Stage II, IIIA, IIIB (with nodal involvement \[N2\]) non-small cell lung cancer (NSCLC). The primary hypothesis is that intismeran autogene plus pembrolizumab is superior to placebo plus pembrolizumab with respect to disease-free survival (DFS) as assessed by the investigator.