VSIR and familial pancreatic carcinoma: The TME of PDAC has demonstrated the expression of VISTA and PD-L1 on distinct subpopulations of CD68+ macrophages, with the VISTA pathway resulting in a more pronounced reduction in CD8 T cell responses and a significant infiltration of TAM with MDSC, implying that VISTA may be more important than PD-L1 in pancreatic cancer [11].