Melanoma patients who responded to nivolumab (PD-1 antibody) were enriched with F. prausnitzii, B. thetaiotamicron, and H. filiformisMelanoma patients who responded to pembrolizumab (another PD-1 antibody), their gut microbiota enriched with D. formicogenerans. Here, PDCD1 is linked to melanoma.