The goal of this study is to learn if people who receive intismeran autogene and pembrolizumab after surgery are cancer-free longer than people who receive placebo and pembrolizumab. Researchers want to know if giving intismeran autogene and pembrolizumab after surgery can help prevent the cancer from coming back in people with non-small cell lung cancer (NSCLC) whose tumors did not respond completely to treatment before surgery (neoadjuvant treatment).