Adenocarcinoma of Stomach

This is a prospective, single-center, single-arm, open phase II clinical study. Forty-nine participants with pathologically or cytologically confirmed gastric cancer or gastroesophageal junction cancer are scheduled to be enrolled in this study. All participants will be treated with 2 to 8 cycles of adebrelimab, apatinib, oxaliplatin, and tigio before surgery. Participants will evaluate the treatment effect after every 2 cycles of medication. By the investigator assessment as an operable subject, apatinib was discontinued for one cycle. The adjuvant treatment will be determined by the investigators based on the participants' postoperative pathology results. Participants requiring adjuvant therapy, with a postoperative interval of at least 4 weeks, but not more than 10 weeks. When the resection standard isn't met for 8 cycles of treatment, the treatment is switched to a maintenance phase, which the subject treatment regimen is determined by the investigator. During the treatment period, participants will receive the study drugs on Day 1 of each 21-day cycle until evidence of disease progression or unacceptable toxicity.