CD4 and neoplasm: Low-dose irradiation, e.g. 0.5-2 Gy, though insufficient to trigger anticancer response, may recruit tumor-specific CD8+ and CD4+ T lymphocytes into the tumor and reverse tumor immune desertification [38].Though only 20 Gy was investigated in our data, further studies elucidating the effect of more dose-fractionation regimens on T cell infiltration and exhaustion are necessary to help us optimize the combination strategies with ICI.