The ASTRUM-006 study compared the efficacy of serplulimab combined with neoadjuvant SOX chemotherapy versus neoadjuvant and adjuvant SOX chemotherapy alone in patients with PD-L1-positive resectable gastric or gastro-oesophageal junction adenocarcinoma. The group receiving serplulimab achieved significantly better event-free survival outcomes. The safety profile was superior in the serplulimab group compared to chemotherapy alone. The perioperative strategy with serplulimab allowed for reduced adjuvant chemotherapy dosing. Extended follow-up is needed to confirm the advantage in overall survival.