Substudy 01I: A Study of Investigational Agents in Participants With Previously Treated Stage IV Squamous Non-small Cell Lung Cancer (NSCLC) (MK-3475-01I/KEYMAKER-U01I)

Researchers are looking for other ways to treat metastatic squamous non-small cell lung cancer (NSCLC). Squamous NSCLC is cancer that starts in squamous cells, which are flat cells that line the inside of the airways in the lungs. Metastatic means the cancer has spread to other parts of the body. Standard treatment (usual treatment) for metastatic squamous NSCLC is immunotherapy with or without chemotherapy. Immunotherapy is a treatment that helps the immune system fight cancer. Chemotherapy is medicine that destroys cancer cells or stops them from growing. However, standard treatment may not work or may stop working to treat metastatic squamous NSCLC. Researchers want to learn if study treatments that are antibody drug conjugates (ADCs) can treat metastatic squamous NSCLC that did not respond (get smaller or go away) to standard treatment. An ADC attaches to a protein on cancer cells and delivers treatment to destroy those cells. The main goals of this study are to learn about: * The cancer response to the study treatments compared to chemotherapy * The safety of the study treatments and if people tolerate them This study is one of the substudies being conducted under one pembrolizumab umbrella master protocol (MK-3475-U01/KEYMAKER-U01).