The purpose of this research study is to learn more about a new medicine called olomorasib, to see if it can help treat lung cancer. We want to see if olomorasib, when used along with standard immunotherapy (pembrolizumab or durvalumab), works well for people with a certain type of lung cancer called KRAS G12C-mutated non-small cell lung cancer (NSCLC) after they’ve had their first treatment. In this study, some people will get olomorasib, and others will get a placebo. Olomorasib is the investigational study drug in this study, and it is not approved by the United States Food and Drug...