CD274 and neoplasm: TNBC exhibits highly heterogeneous responses to immune checkpoint blockade (ICB), where high tumor mutational burden (TMB) correlates with exceptional efficacy, while PD-L1 and tumor-infiltrating lymphocytes (TILs) showed no significant predictive value; regulatory T-cell markers were enriched in responders, whereas GARP overexpression was associated with rapid progression and poor prognosis (54).