This phase II trial studies how well atezolizumab works in treating patients with non-muscle invasive bladder cancer that has come back (recurrent) and has not responded to treatment (refractory) with Bacillus Calmette-Guerin (BCG). Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread.

This randomized phase III trial studies Tokyo-172 strain bacillus Calmette-Guerin (BCG) solution with or without a vaccination using Tokyo-172 strain BCG to see how well it works compared with TICE BCG solution in treating patients with bladder cancer that has not spread to muscle. BCG is a non-infectious bacteria that when instilled into the bladder may stimulate the immune system to fight bladder cancer. Giving different versions of BCG with vaccine therapy may prevent bladder cancer from returning.

This phase II trial studies the effect of adding pembrolizumab to gemcitabine in treating patients with non-muscle invasive bladder cancer whose cancer does not respond to Bacillus Calmette-Guerin (BCG) treatment. Chemotherapy drugs, such as gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the patient's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Adding pembrolizumab to gemcitabine may delay the return of BCG-unresponsive bladder cancer for longer period compared to gemcitabine alone.