Likewise, another first-in-human clinical trial recruiting 15 immunotherapy-refractory metastatic melanoma patients ciphered that 2 of those patients gained partial response, especially one who obtained complete response (CR) to PD-1 blockade therapy after FMT, despite the fact that all patients developed at least one irAE in a minimal degree [19]. This evidence concerns the gene PDCD1 and metastatic melanoma.