CTLA4 and neoplasm: In addition, in melanoma, anti-PD-1 monotherapy or anti-PD-1× anti-CTLA-4 antibodies combination therapy increases the expression of VISTA on lymphocytes and thus reshapes the tumor immune microenvironment, resulting in increased expression of PD-L1 in TAMs, increased Treg infiltration and decreased MHC expression on DCs; these results indicate that the tumor cells have acquired drug resistance, which is related to poor prognosis of the patient [202].