PDCD1 and neoplasm: Indeed, in a recently published experiment, an mRNA vaccine encoding for single-chain IL-12 (fusion of the IL-12p40 and IL12p35 subunits), IFN-α, GM-CSF, and IL-15-sushi (fusion of IL-15 to the sushi domain of the IL-15 receptor), managed to overcome resistance to anti-PD-1 treatment in a colon adenocarcinoma murine model, inducing tumor shrinkage and prolonging survival of the treated mice [31].