CTLA4 and neoplasm: Although anti-PD-1/PD-L1 monotherapies, even combination anti-PD-1/PD-L1 with cytotoxic T lymphocyte antigen 4 (CTLA-4) to maximize the blockade of checkpoint pathways can increase tumor-infiltrating T cells in the prostate, it always showed limited benefits in patients with prostate cancer in clinical trials [4, 46].