In this study, we are looking at how a blood test can help determine if patients who have had their bladder surgically removed because of cancer might need extra treatment. This treatment is called immunotherapy, which uses the body's own immune system to fight cancer. The blood test checks for something called circulating tumor DNA (ctDNA). This is a piece of DNA from cancer cells found in the blood. If ctDNA is found, it may mean the cancer is still there even after surgery. Doctors want to see if treating these patients with the medications nivolumab and relatlimab can help them live longer and stop the cancer from growing.

• This study may last several months with regular follow-up visits.
• Patients will need to give blood samples and possibly have scans like CT or MRI.
• There may be side effects from the treatment, but this will be monitored closely.