were found to promote the entry of immunosuppressive enterotropic α4β7+CD4+ regulatory T 17 cells into the tumor microenvironment through the downregulation of mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) expression in high endothelial venules.8 Taken together, these studies indicated that the gut microbiota plays a vital role in regulating immune checkpoint marker expression and associated treatment efficacy. Here, MADCAM1 is linked to neoplasm.