Guru Sonpavde, MD, Dana-Farber Cancer Institute, Boston, MA, discusses a 3-factor model to predict response to atezolizumab in urothelial carcinoma. Specifically, the three factors associated with tumour regression were tumour mutation burden, the blood lymphocyte: neutrophil ratio and visceral sites of metastasis. This interview was recorded at the 2020 Genitourinary Cancers Symposium, held in San Francisco, CA.