CD274 and neoplasm: While higher PD-L1 levels identify patients with favorable outcomes with ICPI-containing regimens compared with chemotherapy alone in all of these studies, concerns around spatial and temporal PD-L1 heterogeneity support a need for more rigorous assessments with other candidate biomarkers, such as tumor mutational burden (TMB) and microsatellite instability high (MSI-H; ref. 4).