Pembrolizumab and Combination Chemotherapy Before Surgery for the Treatment of Muscle-Invasive Bladder Cancer

Inclusion Criteria: * Participants must have histologically confirmed diagnosis of muscle invasive bladder cancer (cT2-T4a, N0-N1, M0 clinical stage per American Joint Commission on Cancer \[AJCC\]). Clinical node-positive (N1) patients are eligible provided the lymph nodes (LNs) are confined to the true pelvis and are within the planned surgical LN dissection template * Histology must be either pure or predominant non-urothelial histology (noted on any TURBT) * Participants must be deemed eligible for cisplatin-based chemotherapy, radical cystectomy (RC) and pelvic lymph node dissection (PLND) by urologist and medical oncologist * Patients must agree to undergo curative intent surgery * TURBT that showed muscularis propria invasion should be within 12 weeks prior to beginning study therapy. Patients must have available tumor tissue from either initial or repeat TURBT, prior to starting study therapy. Archival tumor tissue sample of a tumor lesion (TURBT specimen) should be provided and must contain muscle invasive component, at least \>= T2 tumor. Formalin-fixed, paraffin embedded (FFPE) tissue blocks are preferred to slides. If submitting unstained cut slides, newly cut slides should be submitted to the testing laboratory, preferably within 14 days from the date slides are cut if possible. Patient must be willing to provide tumor tissue for research. Research samples will not be used for any studies unrelated to this trial * Must have clinical non-metastatic bladder cancer…