IL2 and renal cell carcinoma: The treatment of metastatic RCC has evolved from the early, and relatively ineffective, use of single-agent immunomodulatory agents such as interferon-alpha (IFNα) and interleukin-2 (IL-2) [3, 4], to the use of targeted therapeutics such as the multi-kinase and mTOR inhibitors as well as the checkpoint inhibitors.