PDCD1 and neoplasm: At variance, in a preclinical colorectal cancer model, VISTA blockade has been reported to impair the growth of small tumors, while in larger tumors resistant to anti-PD-1/CTLA-4 therapy, adding anti-VISTA led to tumor rejection in half of the cases, in association with increased antigen presentation, reduced myeloid-mediated suppression and increased interactions between T-cells and myeloid cells [231].