The intimate relationship between gut microbiota and cancer immunotherapy

Immunotherapy is widely used to treat a large variety of malignancies and has revolutionized the therapeutic approach to cancer. Major efforts are ongoing to identify biomarkers that predict response to immunotherapy as well as new strategies to improve ICI efficacy and clinical outcomes. Studies have shown that the gut microbiome determines the extent to which ICIs may invigorate the anticancer immune response. Here, the authors review recent studies that have described the effects of the gut microbiota on the efficacy of CTLA-4 and PD-1 inhibitors and outline potential future clinical directions of these findings.