In Greaney and colleagues’ study [35], the same treatment was performed in melanoma patients as in Algazi’s study [34]; the frequency of circulating PD-1 expressing CD4+ and CD8+ T cells was reduced, which indicated the high effectiveness of intratumor IL-12 electroporation on impacting circulating T cell via immunosuppression within the tumor microenvironment. Here, CD4 is linked to melanoma.