PDCD1 and neoplasm: Compared to the combination therapy of anti-PD-1 with anti-VISTA, the combination between anti-CTLA-4 and anti-VISTA (MIH63) shows stronger anti-tumor effect in the squamous cell carcinoma cell model, significantly slowing the growth of the tumor by activating and upregulating CD8+ T cells, converting the exhausted cells into effector CD8+T cells, and promoting the secretion of TNF- α and IFN-γ [90, 91].