PD-L1 expression scores are determined by immunohistochemistry in tumor cells (TC; percentage of PD-L1-expressing tumor cells: TC0 < 1%, TC1 1–5%, TC2 5–50%, and TC3 ≥ 50%) and tumor-infiltrating immune cells (IC; percentage of tumor area: IC0 < 1%, IC1 1–5%, IC2 5–10%, and IC3 ≥ 10%). The gene discussed is CD274; the disease is neoplasm.