PDCD1 and metastatic melanoma: Notably, different ICI treatment plans correspond to the variation in the dominant gut microbiome among responders with metastatic melanoma, indicating that the relationship between the gut microbiome and every ICI therapy needs to be investigated one by one.464 Additionally, ICIs have been found to influence the gut microbiome composition in patients; dynamic alterations in the gut microbiomes of patients undergoing anti-PD-1 immunotherapy during different treatment cycles have been reported.465