IL2 and metastatic melanoma: Talimogene laherparepvec (T-VEC) is the only treatment with regulatory approval for intratumoural administration in unresectable metastatic melanoma, and is recommended in current clinical practice guidelines.40–44 Interleukin-2 (IL-2) is included in guidelines as a systemic treatment for unresectable metastatic melanoma,43,44 and intratumoural administration has also been investigated.45–47