LAUSR

Simple Summary The immune system plays a key role in regulating the growth of tumour cells. Mobilizing the immune system with PD-1/PD-L1 inhibitors has shown clinical benefits in subsets of patients with lung cancer. Currently, PD-L1 tumour expression is the only validated predictive biomarker for PD-1/PD-L1 blockade therapy in these patients. Advancing predictive and prognostic biomarkers will enable personalized immunotherapy approaches and maximize patient benefit. This review aims to summarize the tumour- and non-tumour associated factors that affect the response to immune checkpoint inhibitors.