V-domain Ig suppressor of T-cell activation (VISTA), which is encoded by the VSIR or C10ORF54 gene, is a B7 family member that maintains T-cell quiescence and mediates the immunoinhibitory function of myeloid-derived suppressor cells (MDSCs); therefore, VISTA is a promising immune checkpoint target for cancer immunotherapy [16–18]. The gene discussed is VSIR; the disease is cancer.