Based on these findings, we conducted a phase 3 study (ASTRUM-007) to assess the efficacy and safety of serplulimab in combination with chemotherapy (5-FU plus cisplatin) versus chemotherapy alone as a first-line treatment in patients with advanced or metastatic ESCC with PD-L1 CPS ≥ 1. Here, CD274 is linked to esophageal squamous cell carcinoma.