PIK3CD and B-cell chronic lymphocytic leukemia: The first-in-class oral selective inhibitor of p110δ isoform Idelalisib has been approved for the treatment of hematological malignancies including chronic lymphocytic leukemia (CLL), follicular B-cell non-Hodgkin lymphoma (FL), and small lymphocytic lymphoma (SLL) [15,16], and has shown considerable antitumor activity in the treatment of hematological cancer [17].