CD274 and cancer: Application of PD-L1 expression, tumor mutational burden (TMB), and microsatellite instability (MSI) greatly improves patient selection and predicting responses to treatment (47, 48), but challenges remain in achieving consistent biomarker validation across diverse populations and cancer types, as well as in integrating complex biomarkers like immune cell infiltration and gene expression profiles into routine clinical practice to guide therapy decisions more effectively (49, 50).