Elisa ten Hacken, PhD, Harvard Medical School, Boston, MA, outlines a study which demonstrated that combinatorial in vivo modelling of chronic lymphocytic leukemia (CLL) loss-of-function mutations using multiplexed CRISPR leads to development of both CLL and Richter’s syndrome (RS). This interview took place during the 62nd American Society of Hematology (ASH) Annual Meeting and Exposition, 2020.