VTCN1 and neoplasm: Other immune checkpoint ligands expressed by TAMs potentially also have direct suppressive effects on tumor-infiltrating T cells, such as B7-H4 (aka B7x, B7S1 or VTCN1) and V-domain Ig- containing suppressor of T cell activation (VISTA, aka PD-1H, DD1α), which might confer macrophages immunosuppressive capacity [38–40].