A Study of Investigational Agents in Participants With Previously Treated Stage IV Nonsquamous Non-small Cell Lung Cancer (NSCLC) (MK-3475-01H/KEYMAKER-U01)

Researchers are looking for new ways to treat metastatic nonsquamous non-small cell lung cancer (NSCLC) that has been treated before. Metastatic means the cancer has spread to other parts of the body. Nonsquamous means the cancer did not start in squamous cells, which are flat cells that line the inside of the lungs. Standard treatment (usual treatment) for NSCLC is surgery, then immunotherapy with or without chemotherapy after surgery. Immunotherapy is a treatment that helps the immune system fight cancer. Chemotherapy is a medicine that works to destroy cancer cells or stop them from growing. However, standard treatment may not work or may stop working for some people. Researchers want to know if 2 antibody drug conjugates (ADCs) can help treat metastatic nonsquamous NSCLC that did not respond (get smaller or go away) to treatment. An ADC attaches to specific targets on cancers cells and delivers treatment to destroy those cells. Researchers will compare 2 different ADCs (the study treatments) to chemotherapy in this study. The goals of this study are to learn: * About the safety of the study treatments and if people tolerate them * How many people have the cancer respond to the study treatments