CD8A and pancreatic adenocarcinoma: The findings demonstrated that PAAD cells expressing NPC1L1 function as a checkpoint molecule, thereby inhibiting the cytotoxic activity of anti-tumor CD8+ T cells through the interaction between NPC1L1 and Integrin α L. It can be inferred that the NPC1L1 inhibitor Ezetimibe enhances CD8+ T cell-mediated anti-tumor responses and works synergistically with PD-1 blockers to improve therapeutic efficacy in PAAD treatment.