Lung cancer is divided to Non-Small Cell Lung Cancer (NSCLC) comprising about 85% of lung cancer cases, and small cell lung cancer (15% of lung cancer cases). Non-small cell lung cancer (NSCLC) has several subtypes: a. Adenocarcinoma, b. Squamous cell carcinoma, c. Large cell carcinoma, or d. mixed histology. Treatment of localized NSCLC is surgical resection, stereotactic ablative radiation therapy, or combination of chemotherapy and radiation (chemoradiation). Treatment of advanced / metastatic disease includes targeted therapies, chemotherapy and immunotherapy. 

Immunotherapy for non-small cell lung cancer (NSCLC) is incorporated increasingly in first line treatments protocols. Multiple phase 3 studies have tested different medications targeting programmed death receptor 1 (PD-1), programmed death-ligand 1 (PD-L1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), with or without chemotherapy. The inclusion criteria differ between the various clinical trials, including the cut-off levels of PD-L1 expression on tumor cells, and the tumor histology (squamous or non-squamous).