The stimulatory impact of IL-2 on effector T cells (Teff) and NK cells prompted investigations of high-dose IL-2 for cancer therapy, leading to the approval of recombinant human IL-2 (Aldesleukin) as the inaugural immunotherapy endorsed by the US Food and Drug Administration for managing metastatic renal cell carcinoma (RCC) in 1992 and metastatic melanoma in 1998 [91]. This evidence concerns the gene IL2 and cancer.