CD274 and non-small cell lung carcinoma: By co-culturing the NSCLC cell derived exosomes with cisplatin-sensitive NSCLC cells, the PD-L1 levels in A549 and H1299 cells were significantly upregulated (Fig. 5a, b), suggesting that exosomal PD-L1 approached the cytoplasm of the above NSCLC cells (Fig. 5c).