Abstract
The success of immune checkpoint inhibitors in advanced urothelial carcinoma provides patients with the prospect for durable objective responses. However, the majority of patients do not respond to immune checkpoint blockade. Several potential predictive biomarkers of response have been evaluated in hopes of better identifying likely responders, though each has been shown to have limitations. Going forward, development of reliable predictive biomarkers is imperative. Likewise, innovative treatment combination approaches to convert non-responders to responders are essential to continue making progress in the field.