CD274 and neoplasm: This may be due to tobacco carcinogens that cause mutations in tumor occurrence, causing a more new antigen and the increase of the PD-L1 expression, and in addition, smoking can induce inflammation, including T cells and inflammatory cytokines, such as interferon-g, and can raise PD-L1 expression [21], but this research shows smoking status in patients with no statistical difference with PD-L1 expression, requiring a larger sample size study to confirm further.