CXCR4 and B-cell chronic lymphocytic leukemia: We, therefore, conclude that identification of CXCL12–CXCR4–STAT3 axis as a pivotal immune-modulatory axis in CLL could provide needed impetus for the design of new therapeutic strategies in CLL or inform different approaches to the use of available immunomodulatory agents, such as lenalidomide in this disease.