In many types of human cancers, including hepatocellular carcinoma, pancreatic cancer, and ovarian cancer, TI-Treg cells suppress antitumor activity by secreting the anti-inflammatory cytokines TGF-β and IL-10 and by upregulating the expression of inhibitory immune checkpoint receptors, including CTLA-4, GITR, TIM-3, and ICOS [7, 29, 59–64]. The gene discussed is TNFRSF18; the disease is cancer.