Pembrolizumab in Muscle-invasive Bladder Cancer

Inclusion Criteria: Subject must meet all of the following applicable inclusion criteria to participate in this study: * Written informed consent and HIPAA authorization for release of personal health information prior to registration. NOTE: HIPAA authorization may be included in the informed consent or obtained separately. * Age ≥ 18 years at the time of consent. * ECOG Performance Status of ≤ 1 within 28 days prior to registration. * Histological evidence of clinically localized muscle-invasive urothelial cancer of the bladder. Clinical stage cT2-3N0M0. N0 will be considered the absence of radiographically enlarged lymph nodes on baseline imaging. Patients with lymph nodes \<1 cm in long axis on imaging may be eligible but must be discussed with the sponsor investigator. * Have undergone a standard of care maximal transurethral resection of bladder tumor ≤ 60 days prior C1D1. Maximal TURBT is defined as a macroscopically complete resection of bladder tumor when safely possibly per the treating urologist. Patients who cannot safely undergo maximal TURBT as per their treating urologist are eligible for enrollment but should be discussed with the sponsor investigator. * All subjects must have adequate transurethral resection of bladder tumor tissue available for submission (i.e., at least 15 unstained slides or paraffin block) identified during screening. This tissue can be from the maximal restaging TURBT, a prior diagnostic TURBT revealing muscle-invasive bladder cancer, o…