PDCD1 and lymphoma: Mechanistically, targeted disruption of the PD-1/PD-L1 axis serves as a dual-pronged immunotherapeutic strategy: not only potentiating host anti-lymphoma immunity through checkpoint reversal, but also enhancing CAR-T cell effector functions by mitigating terminal exhaustion phenotypes thereby synergistically improving therapeutic efficacy in B-cell malignancies [47,48].