VSIR and melanoma: The inhibitory function of VISTA in anticancer immunity was demonstrated in mice transplanted with melanoma, in which blocking of VISTA induced antitumor immunity by increasing tumor-specific CD4+ and CD8+ T cells and decreasing FoxP3+ regulatory T cells in the tumor microenvironment.10 Genetic deletion of VISTA (Vsir) resulted in increased production of inflammatory cytokines and chemokines in a mice model16.