TP53 and B-cell chronic lymphocytic leukemia: Consistent with this idea, examination of human LN cells from a patient with aggressive CLL (de novo TP53‐mutated U‐CLL patient, requiring immediate treatment) revealed a striking expansion of a Ki67hiCXCR4hiCD5hi fraction in the LN compared to the PB compartment (Supporting Information S1: Figure 4a–c).