CD274 and esophageal squamous cell carcinoma: Notably, this improvement was even more pronounced in patients with tumor PD-L1 expression ≥1%, where the median DoR in the O+Y group more than doubled compared to the chemotherapy-alone group (11.8 months vs. 5.7 months).These trials collectively validated PD-1/PD-L1 inhibitors in ESCC across treatment lines and supported biomarker-driven approvals, reshaping therapeutic paradigms.