Keeping the bladder has long been one of the biggest challenges for people whose high-risk bladder cancer returns after standard treatment. Their phase 3 study examined an immunotherapy called cretostimogene grenadenorepvec in patients whose cancer returned after BCG treatment. BCG has been the main treatment for high-risk bladder cancer that has not grown into the bladder muscle. Safety is another important part of any cancer treatment. Overall, the publication in The Lancet Oncology represents a major step toward more personalized and less invasive bladder cancer care.