To date, despite major efforts in developing and testing PI3K inhibitors in clinical trial, the isoform-selective PI3K inhibitor CAL-101 (idelalisib, GS1101), targeting p110δ in the treatment of chronic lymphocytic leukemia, small lymphocytic lymphoma and follicular lymphoma is the only FDA approved agent and only few other agents have reached phase III trial stage (Supplementary Table S1). Here, PIK3CD is linked to B-cell chronic lymphocytic leukemia.