Evidences showed that tumor-reactive CD39+CD8+ T cells isolated from human malignancies exhibit exhaustion phenotypes, including decreased production of IFN-γ, IL-2 and TNF-α and overexpression of several checkpoint receptors such as PD1, TIM3, LAG3, TIGIT and 2B4 [10]. This evidence concerns the gene ENTPD1 and neoplasm.