The purpose of this study is to evaluate the effects, good or bad, of targeted therapies or immunotherapy (drugs that help the body's immune system fight cancer cells) in patients who have solid tumors with specific genetic alterations or with a high number of mutations. Patients will be assigned to cohorts (groups) based on having a specific type of genetic alteration in their tumor. The study includes cohorts for patients whose tumors have genetic alterations in the ROS1, NTRK, PIK3CA, BRAF, or RET genes or a high number of mutations in their tumor.