Therapeutically, combination strategies informed by mechanistic insights—such as PD-1 plus CD39/CD73 blockade or photodynamic therapy (PDT) combined with PD-1/PD-L1 inhibitors—hold promise for selectively depleting or reprogramming suppressive CD39+PD-1+ Tregs and enhancing abscopal immunity in melanoma models (89). This evidence concerns the gene PDCD1 and melanoma.