Upon inhibition of MARCO, macrophages release TNF-related apoptosis-inducing ligand (TRAIL) promoting natural killer (NK) cell-mediated killing and results in downmodulation of Tregs, reduction of IL-10, and reestablishes cytotoxic T cell activity [37]; Therefore, anti-MARCO antibody treatment used in combination with T cell-directed immunotherapy, such as antibodies to PD-1 or PD-L1 May provide a promising approach to combinatorial immunotherapy for melanoma. Here, PDCD1 is linked to melanoma.