Thirdly, the included studies employed two methodologies to evaluate PD-L1 expression: Tumor Proportion Score (TPS), defined as the percentage of PD-L1 positive tumor cells out of the total number of viable tumor cells, and Combined Positive Score (CPS), which accounts for the ratio of PD-L1 expressing tumor cells, lymphocytes, and macrophages to the total number of viable tumor cells (37). The gene discussed is CD274; the disease is neoplasm.