The landscape for the second- and third-line treatment of advanced non–small cell lung cancer has changed dramatically over the last two decades. Immunotherapeutic agents have become a preferred choice following progression on platinum-based first-line chemotherapy. However, there remains a role for cytotoxic chemotherapy and pemetrexed and docetaxel (with or without ramucirumab) are approved for single-agent use in the second-line setting. With the discovery of new genetic alterations and the development of novel targeted drugs, the treatment of advanced non–small cell lung cancer following progression on first-line therapy continues to become more complicated as new treatment algorithms evolve.