Expression of CC-chemokine receptor 4 (CCR4), which is commonly expressed on T helper (Th) cells and Treg cells, is typically activated via CC-chemokine ligand 17 (CCL17) and CCL22 secreted by Reed-Sternberg cells of Hodgkin lymphoma, enhancing both CAR T cell migration to tumors and antitumor efficacy in a mouse xenograft model of Hodgkin lymphoma [181]. Here, CCR4 is linked to Hodgkins lymphoma.