This selective PD-1 degradation in CD8+ T cells resulted in an anti-tumor response, comparable to that observed in Rosa26LSL-OsTIR1/+;Pdcd1AID/AID;VavCre mice in the MC38 xenograft model (Fig. 5h, i and Supplementary Fig. 6e), thereby implying that the therapeutic anti-tumor effects associated with anti-PD-1 therapy predominantly stem from the inhibition of PD-1 signaling within CD8+ T cells. This evidence concerns the gene PDCD1 and neoplasm.