PDCD1 and cancer: Although low-dose dexamethasone at the initial stage of treatment is helpful to improve the efficacy of anti-PD-1 treatment in cancer by suppressing immune evasion (11, 12), but high-dose synthetic GCs such as dexamethasone and prednisolone are found to suppress T cell proliferation and function and decrease response to anti-PD-1 and anti-CTLA-4 immune checkpoint blockade in vitro and animal experiments (13, 14).