ERBB2 and gastric cancer: The CheckMate 649 trial demonstrated that nivolumab combined with XELOX (capecitabine and oxaliplatin) significantly improved OS, PFS, and objective response rate compared to XELOX alone in patients with metastatic, non-HER2-positive gastric cancer, especially those with PD-L1 combined positive scores (CPS) ≥5 (22).