Data from recent studies indicate that PD-1 and PD-L1/PD-L2 mediate immune evasion in chronic lymphocytic leukemia (CLL), highlighting their importance in this malignancy. In this interview, Anthony Mato, MD, MSCE, of the University of Pennsylvania, Philadelphia, PA, discusses the Phase I/II study of pembrolizumab in combination with ublituximab and umbralisib in patients with relapsed/refractory CLL (NCT02535286). Notably, this was the first ever study of PI3K-? inhibiton in combination with anti-PD-1 therapy in CLL patients. This interview was recorded at the American Society of Hematology (ASH) 2017 Annual Meeting and Exposition in Atlanta, GA.