This increase in checkpoint inhibitors is also seen in animal models of HIV‐infection, with PD‐1 expression increasing on CD4+94 and CD8+ T cells,95, 96 and Tim‐397 and TIGIT91 expression increasing on CD8+ T cells following infection of nonhuman primates (NHPs) with simian immunodeficiency virus (SIV). This evidence concerns the gene PDCD1 and infection.