Cancer immunotherapy: the PD-L1 pathway The role of the immune system is to protect the body from foreign invaders. In responding to cancer, T cells play a central role in the immune system. Programmed death ligand 1 (PD-L1) is one of the inhibitory ligands that, under normal conditions, help maintain immune homeostasis. In many cancers, however, PD-L1 can help tumour cells evade immune system surveillance. To learn more about Roche’s commitment to cancer immunotherapy, visit To learn more about our cancer immunotherapy research, visit Subscribe to our YouTube channel now: Get in touch with us: Roche has been committed to improving lives since the company was founded in 1896 in Basel, Switzerland. Today, Roche creates innovative medicines and diagnostic tests that help millions of patients globally. Roche is a leader in research-focused healthcare with combined strengths in pharmaceuticals and diagnostics. Roche is the world’s largest biotech company, with truly differentiated medicines in oncology, immunology, infectious diseases, ophthalmology and neuroscience. For more information and insights visit: