CD274 and non-small cell lung carcinoma: Additionally, clinical trials have also explored the associations between tumor expression indicator PD-L1 and survival, and it has been found that the OS and PFS were significantly longer than chemotherapy users when the patient had more PD-L1 expression.[12, 13, 16] Among the NSCLC patients in this study, PD-L1 expression was positive for 4 cases.