PDCD1 and melanoma: Immune competent C57BL/6 mice were subcutaneously inoculated with SMM103 melanoma cells, the mice were randomly divided into four groups when the tumor grew up to ≈80 mm3 and were treated with saline, anti-PD-1 (5mg/kg, i.v.), sirolimus (2mg/kg, i.p.), anti-PD-1 plus sirolimus, respectively, as depicted on experiment scheme (Figure 4C).