This study is looking at the safety of using **propranolol hydrochloride** (a medicine that helps with heart problems) with **immune checkpoint inhibitors** (ICI) in treating **urothelial carcinoma** (a type of bladder cancer). The study has three goals: checking for any side effects, seeing how well the treatment works, and understanding changes in certain blood cells. There are two groups in the study. One group gets both propranolol and an ICI, and the other group gets only an ICI. ICIs help the body's immune system fight cancer. Participants will receive either **Pembrolizumab**, **Avelumab**, or **Nivolumab**, depending on what their doctor thinks is best.
- The study lasts up to 2 years with regular check-ups every 12 weeks after treatment.
- Participants must be 18 or older and have urothelial carcinoma.
- Women must have a negative pregnancy test and use birth control during the study.
People with certain heart problems or who are on other specific medications may not be able to join. The study aims to see if combining these drugs is safe and if it helps fight the cancer better.