CD274 and neoplasm: Given the lack of evidence, the role for chemotherapy or radiation remains undetermined.[17] Ferris et al suggested that a PD-L1 expression level of 1% or more tended to be associated with a better overall survival.[18] In this case report, PD-L1 expression was determined by using Combined Positive Score (CPS), which is the number of PD-L1 staining cells (tumor cells, lymphocytes, and macrophages) divided by the total number of viable tumor cells, multiplied by 100.