CD70 and neoplasm: In the CD70-KO system, CD8+/granzyme A+ and CD8+/perforin+ T cell fractions, secretion of TNF-α and IFN-γ, as well as CD8+ T cell proliferation were elevated, and expression of PD-1 and TIM-3 was diminished (Figs. 3m–q and Supplementary Fig. 3n), suggesting that impaired Treg suppressive activity could re-activate anti-tumor CD8+ T cells.