Disparate clinical activity of PD‐1 blockade in melanoma subtypes: Know thy enemy!

The 2 articles by Shousatri et al and Algazi et al in this issue of Cancer report the efficacy of programmed cell death receptor 1 (PD‐1) pathway blockade in metastatic acral/mucosal melanoma and uveal melanoma, respectively. The results point to the disparate activity of PD‐1 and PD‐1 ligand pathway blockade in these subtypes of melanoma and highlight the need to understand differences in the underlying biology of immune evasion in these and other malignancies as well as the need to identify mechanisms of success and failure of PD‐1 blockade. See also pages 3344‐53 and 3354‐62.