IL-2 promotes CD8+ T cell recognition and clearance of malignant cells for cancer immunotherapy in the early tumor stage, but sustained high levels of IL-2 in the tumor microenvironment induce CD8+ T cell depletion and dysfunction of T cells thus suppressing anti-tumor immunity (Y. Liu et al. 2021; MacDonald et al. 2021). This evidence concerns the gene CD8A and neoplasm.