CD274 and neoplasm: This may be due to well-evolved tumour immune escape mechanisms, such as a reduced expression of major histocompatibility complex class I (MHC I), resulting in decreased immune recognition,11 and an immunosuppressive tumour microenvironment present in advanced disease.44 However, it is clear that the minority of patients who respond to PD-1/PD-L1 blockade can derive substantial benefit and that the responses can be durable.