IL2 and renal carcinoma: The protagonists in the field of immuno-oncology are certainly interleukin-2 (IL-2), the first cytokine FDA approved for therapeutic purposes, IL-12, -15, -21, and interferon alpha (IFN-ɑ), for a long time used for the treatment of hematological neoplasms, for renal carcinoma and melanoma [240].