Previous work with transgenic expression of potent cytokines or chemokines such as GM-CSF, Flt3L, or IP-10 in B16 melanoma cells only displayed anti-tumor activity when combined with immune checkpoint blockade or after prophylactic immunization with irradiated cells expressing these cytokines prior to challenge with live tumor cells [30, 32], but never as single agents as observed with mLIGHT. Here, FLT3LG is linked to melanoma.