The intestinal microbiota determines the clinical efficacy of immune checkpoint blockers targeting PD-1/PD-L1

Cancer immunotherapists have been searching for biomarkers predicting patient responses to PD-1/PD-L1 blockade in neoplastic cells as well as in the immune system. Now, accumulating evidence indicates that the composition of the intestinal microflora has a major impact on patient prognosis. Here, we enumerate the bacterial species that are associated with favorable outcome of immunotherapy.