Functional analysis of the different CD8 T cell populations from tumor and healthy tissues showed that fewer than 20% of tumor-derived PD1+CD39+ TEX produced IFN-γ and TNF, while about 80% of PD1+CD39− CD8 T cells from normal human tissue, NAT, and liver tumor tissue produced these cytokines after restimulation (Fig. 6 E). This evidence concerns the gene PDCD1 and neoplasm.