CD274 and neoplasm: On the contrary, PD-L1 protein expression in KEYNOTE-355 was determined using Combined Positive Score (CPS) (PD-L1 IHC 22C3 pharmDx, Agilent, Santa Clara, CA), defined as the number of PD-L1 staining cells (tumour cells, lymphocytes and macrophages) divided by the total number of viable tumour cells, multiplied by 100 [47].