PDCD1 and melanoma: In this model of aggressive advanced melanoma, all three treatment arms had statistically significant reduced tumor burdens compared to the controls (SAM, 646 mm3, p < 0.05; anti-PD-1, 567 mm3, p < 0.05; and control 1,020 mm3), whereas the combination group of SAM+anti-PD-1 had significantly lower mean tumor volume (315 mm3) relative to control (p < 0.0001) and SAM (p < 0.05) at the end point (Figure 2A).