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Blocking Programmed Death–1 (PD-1) can reinvigorate exhausted CD8 T cells (T_EX) and improve control of chronic infections and cancer. However, whether blocking PD-1 can reprogram T_EX into durable memory T cells (T_MEM) is unclear. We found that reinvigoration of T_EX in mice by PD-L1 blockade caused minimal memory development. After blockade, reinvigorated T_EX became reexhausted if antigen concentration remained high and failed to become T_MEM upon antigen clearance. T_EX acquired an epigenetic profile distinct from that of effector T cells (T_EFF) and T_MEM cells that was minimally remodeled after PD-L1 blockade. This finding suggests that T_EX are a distinct lineage of CD8 T cells. Nevertheless, PD-1 pathway blockade resulted in transcriptional rewiring and reengagement of effector circuitry in the T_EX epigenetic landscape. These data indicate that epigenetic fate inflexibility may limit current …