In preclinical studies, it was found that although the use of A2aR inhibitors alone did not increase the frequency of antigen-specific CD8+ T cells, the dual blockade of PD-1 and A2aR significantly increased the proportion of tumor-infiltrating CD8+ T cells and the production of IFN-γ and Granzyme B and improved the survival rate of tumor-bearing mice (132, 133). This evidence concerns the gene PDCD1 and neoplasm.