PD-1/PD-L1 immune checkpoint blockade in non-small cell lung cancer.

The programmed death 1 (PD-1) pathway is an immune checkpoint that has been implicated in tumoral immune escape, and has emerged as a major focus of immunotherapy in non-small cell lung cancer (NSCLC). Multiple agents have progressed through clinical development in recent years, including antibodies targeting both PD-1 and its key ligand, programmed death ligand 1 (PD-L1). This article reviews PD-1/PD-L1 blockade in NSCLC, including completed clinical trials, ongoing studies, future directions, and challenges.