Immune checkpoints are regulatory pathways in the immune system that prevent overactivation of immune responses, which could harm normal tissues. Cancer cells often exploit these checkpoints to avoid immune destruction. Checkpoint inhibitors, such as [PD-1/PD-L1](https://) and [CTLA-4](https://) inhibitors, are a class of drugs designed to block these pathways, thereby enhancing the ability of lymphocytes to target cancer cells.
