CXCR5 and B-cell chronic lymphocytic leukemia: In CLL, where PD‐1 ICB does not induce clinical responses, CXCR5+PD‐1+ CD8 T cells show increased differentiation ex vivo, and altered differentiation toward effector populations after stimulation, indicating that functional modulation by the CLL microenvironment could hamper responses to PD‐1 ICB.