Berner F, et al. - In order to gain insight into the underlying pathophysiologic processes of autoimmune skin toxic effects induced by anti–PD-1 (programmed cell death 1) therapy in patients with non–small cell lung cancer, researchers conducted this cohort study of 73 patients with non–small cell lung cancer who received anti–PD-1 therapy. Among these, 25 developed autoimmune skin toxic effects; patients with complete remission or partial remission vs those with progressive or stable disease presented these toxic effects more frequently. Autoimmune skin toxic effects seemed involving T cells that reacted to antigens shared in non–small cell lung cancers and the skin. Also, patients who responded to therapy show the mediatory role of these T cells in the tumor regression. Findings thereby support the predictive value of autoimmune toxic effects associated with checkpoint blockade for clinical responses and their capability in providing opportunities to identify cancer T-cell targets.