This study employs a randomized, controlled, exploratory clinical trial design, with a planned enrollment of 66 patients who have previously failed systemic chemotherapy for recurrent/metastatic gastric cancer,
1. Patients with advanced gastric adenocarcinoma or gastroesophageal junction adenocarcinoma diagnosed by histology or cytology;
2. Patients who have previously failed first-line treatment including systemic chemotherapy and immune checkpoint inhibitors, and have maintained first-line use of immune checkpoint inhibitors for at least 3 months;
3. According to the evaluation criteria for solid tumor efficacy 1.1 (RECIST v1.1), there should be at least one measurable lesion that has not received local treatment such as radiotherapy (lesions located within the previously irradiated area can also be selected as target lesions if progression is confirmed);
4. ECOG score: 0-1 point;
1. History of gastrointestinal perforation and/or fistula within 6 months prior to the first use of medication;
2. There is uncontrollable pleural effusion, pericardial effusion, or peritoneal effusion that requires repeated drainage;
3. History of allergies to any component of Adebrelimab in the past;
Received any other investigational drug within 4 weeks prior to the first use of the investigational drug or had a half-life of no more than 5 from the last investigational drug;