One of the current most effective CAR T cell therapies targets CD19, an antigen expressed by B cells in all stages of development until differentiation in plasmocytes, including B cell malignancies, such as Hodgkin (HL) and non-Hodgkin lymphoma (NHL), acute (ALL) or chronic lymphocytic leukemia (CLL) [4]. Here, CD19 is linked to B-cell chronic lymphocytic leukemia.