CD274 and non-small cell lung carcinoma: To select a suitable cell line for screening, we measured basal and IFN-γ-induced PD-L1 expression levels in seven non-small-cell lung cancer (NSCLC) cell lines (H2009, HCC44, HCC461, H460, H647, H2122, and A549) and chose H2009 due to it having the highest basal and IFN-γ-induced PD-L1 levels (Fig. 1a, b and Supplementary Fig. 1b, c).