IL2 and metastatic melanoma: The FDA has approved the clinical usage of high-dose of IL-2 for the treatment of patients with metastatic melanoma [45], but at the same time, the induced severe systemic toxicity, including hypotension, capillary leak syndrome, oliguric renal failure and hypoxia was reported [46]; therefore, it is necessary to transit to other interleukins for obtaining the benefits but with fewer adverse events.