PDCD1 and melanoma: Further, in a human phase 1 clinical trial with melanoma patients (n=10), three of the patients treated with FMT showed desirable changes in gene expression in the tumor microenvironment and in another human phase 1 clinical trial, a subset of melanoma patients (n=6) revealed that a combination of FMT and anti-PD-1 contributed to a change in the microbiota and a reprogramming of the tumor environment which allowed for the overcoming of resistance to anti-PD-1 (67).