PDCD1 and B-cell chronic lymphocytic leukemia: As we and others have recently highlighted clear differences in the phenotype of T cells in peripheral blood compared to LNs in CLL, with a phenotype of T-cell activation and exhaustion only in the tissue but not in blood [34, 36], we investigated the abundance and frequency of EOMES+ PD-1+ TR1-like cells in secondary lymphoid organs (SLO) of patients.