Recently, a phase Ib clinical study demonstrated that the combination of talimogene laherparepvec [T-VEC, a human granulocyte-macrophage colony-stimulating factor (GM-CSF)-encoding oncolytic herpes simplex virus 1 (HSV-1)] and pembrolizumab (Keytruda, the first FDA-approved PD-1 inhibitor) has greater efficacy in the treatment of melanoma than either therapy alone [7]. This evidence concerns the gene CSF2 and melanoma.