PDCD1 and neoplasm: In experimental mouse models after exposure to hypofractionated RT a strong upregulation of PD-L1 was observed (radiation and anti-PD-L1 treatment synergistically promote antitumor immunity in mice), so we can suppose that the combination of the PD-1/PD-L1 blockade and RT may overcome tumor immunosuppression and improve the systemic effect of RT.