CD8A and melanoma: In a clinical study of melanoma, fecal-microbiome transplantation (FMT) and pembrolizumab (anti-PD-1) provoked CD8+ T-cell activation in the TMEs of nonresponding melanoma patients through the modulation of several cytokines and chemokines that provoked resistance to anti-PD1, increasing the efficacy of and overcoming immune resistance to immunotherapy [151].