Clinical development of immune checkpoint blockade has dramatically changed the treatment paradigm and prognosis for patients with non–small cell lung cancer. Immune checkpoint blockade with PD-1 and PD-L1 antibodies generates clinically significant, durable responses in patients with advanced non–small cell lung cancer. These agents are approved for first- and second-line treatment, either as single agents or in combination with chemotherapy and angiogenesis inhibitors . Although the toxicity profile of these treatments is favorable, a unique set of immune-mediated adverse events, such as pneumonitis, has been observed. Broader use of these agents is improving survival for patients with advanced lung cancer.