PDCD1 and neoplasm: Nowadays, due to deep studying and enhanced understanding of the tumor microenvironment (TME) and molecular profiling of bladder cancer, immunotherapies targeted at programmed cell death protein 1 (PD-1) and its ligand programmed cell death protein ligand 1 (PD−L1) have been developed over the past several years and expected to improve the survival outcome of patients with BCa in the future (12).