Consistent with the results observed in chronically infected mice and cancer patients, the frequency of TCF1+Tim-3- cells among PD-1+ CD8+ T cells was much higher in the spleen than that in the blood and liver at both time points, 7 and 28 dpt (Fig. 4A–D), suggesting the universal properties of TCF1+PD-1+ CD8+ T cells in their localization into the lymphoid tissues in the microenvironment with persistent antigenic stimulation. Here, PDCD1 is linked to cancer.