Cigarette smoke extract (CES) was prepared30 and used to treat 16HBE (normal lung epithelial cells) and H460 (NSCLC) cells, and the results showed that treatment of the cells with 20 – 40% of CES significantly upregulated PD-L1 at both mRNA (Fig. 1b) and protein (Fig. 1c) levels. This evidence concerns the gene CD274 and non-small cell lung carcinoma.