Drug class: Immune checkpoint inhibitors (PD-L1 inhibitor) Mechanism of Action Atezolizumab is a humanized monoclonal antibody that blocks programmed death ligand 1 (PD L1). Normally, PD L1 binds to tumour-specific T cell receptors, suppressing immune activity and preventing tumour destruction (1,2). As an immune checkpoint inhibitor, atezolizumab reactivates the immune response by binding PD-L1 on cancer cell surfaces, promoting tumour cell elimination. It is approved for mu