These studies showed that just prior to increases in patient viremia, PD‐1 levels increased on HIV‐specific CD8 T cells and these cells exhibited reduced in vitro capacity to kill HIV‐infected cells.85 As such, a delicate balance may exist between T‐cell–mediated control of viral infection and the progressive development of T‐cell exhaustion. The gene discussed is PDCD1; the disease is viral infectious disease.