For example, talimogene laherparepvec (T-VEC), an oncolytic virus FDA approved for the treatment of advanced melanoma, has been engineered to selectively replicate within tumors and to promote the priming of T cell responses and produce granulocyte–macrophage colony-stimulating factor (GM-CSF) to enhance systemic antitumor immune responses [308]. Here, CSF2 is linked to melanoma.