PDCD1 and urinary bladder carcinoma: The most attentive checkpoint targets in bladder cancer treatments are programmed cell death protein-1 (PD-1), programmed death ligand-1 (PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) (Sundararajan and Vogelzang 2015; van Hooren et al., 2017).