A review of the PD-1/PD-L1 checkpoint in bladder cancer: From mediator of immune escape to target for treatment1

PD-1 is one of several key receptors mediating immune escape, and agents targeting its ligand PD-L1 have already been successfully applied to patients with metastatic urothelial cancer. More research is needed to standardize criteria for PD-L1 positivity, explore its use as a biomarker, and optimize its use in the treatment for bladder cancer.