Nevertheless, our data demonstrated that the KO αβ T cells exhibited upregulated expression of both inhibitory (e.g., Pdcd1/PD-1, Ctla4) and costimulatory (e.g., Tnfrsf9/4-1-BB, Tnfrsf18/GITR, and Tnfrsf4/OX40) genes (Figure 3B), a phenomenon that has been documented in T cells within the tumor microenvironment (12, 49). This evidence concerns the gene PDCD1 and neoplasm.