CD274 and non-small cell lung carcinoma: To investigate the mechanism underlying the cooperative effect of IL-1β and IFN-γ on PD-L1 expression in NSCLC cells, we examined the activation of downstream signaling events by these cytokines in the H1437 and II-18 cells, both of which showed a synergistic effect of IL-1β and IFN-γ on PD-L1 expression, as well as in H322 cells, which showed an effect only of IFN-γ.