Programmed Death-Ligand 1 (PD-L1) is a protein expressed on the surface of cells. It plays a crucial role in suppressing the immune system by binding to the PD-1 receptor on T-cells, effectively reducing the immune system's ability to attack cells, including cancer cells. In the context of cancer, PD-L1 can be overexpressed on the surface of tumor cells, helping them evade immune detection and destruction.
