programmed death-ligand 1

Programmed death-ligand 1 (PD-L1) is a protein found on the surface of some cells, including certain cancer cells. Its role is to help the body regulate immune responses by binding to the PD-1 receptor on immune cells, effectively telling the immune system to pause attacking. Cancer cells can produce PD-L1 to evade immune detection and destruction. Therapies called immune checkpoint inhibitors block PD-L1 or PD-1, preventing this "pause" signal, which helps the immune system recognize and attack cancer cells more effectively.