The elevated probiotic or commensal gut microbiome is associated with PD-1 responsiveness in numerous cancer types; Prevotella in gastrointestinal cancer, Akkermansia muciniphila with non-small cell lung cancer, and renal cell carcinoma, Bifidobacterium longum in non-small cell lung cancer, and Lactobacillus metastatic melanoma [128,129,130,131,132]. The gene discussed is PDCD1; the disease is cancer.