This study is a multicenter, randomized, uncontrolled clinical trial to evaluate the efficacy and safety of camrelizumab combined with or without apatinib and SOX of neoadjuvant treatment for resectable locally advanced gastric or gastroesophageal junction adenocarcinoma.

Inclusion Criteria:

1. Has previously untreated localized gastric or GEJ adenocarcinoma as defined by T3-4N+M0 (according to AJCC 8th edition) ;
2. Plans to proceed to surgery after completion of neoadjuvant therapy;
3. Has an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1.
4. Has adequate organ function.
5. Female subjects of childbearing potential must have a negative serum pregnancy test within 72 hours prior to the first dose, and be willing to use a highly effective method of contraception during the study and for 2 months after the last dose of carrelizumab or 8 weeks after apatinib or 6 months after chemotherapy drugs, whichever is longer.
6. Male subjects whose partners are women of reproductive age should be surgically sterilized or agree to use highly effective methods of contraception during the study and for 2 months after the last administration of carrilizumab or 8 weeks after apatinib or 3 months after chemotherapy drugs, whichever is longer. Sperm donation is not allowed during the study.

Exclusion Criteria:

1. Known HER2 positive;
2. Known peritoneal metastasis or positive peritoneal cytology (CY1P0) or T4b (according to AJCC 8th edition);
3. Previous or concurrent malignancies, except for cured basal cell carcinoma of skin, carcinoma in situ of cervix, and carcinoma in situ of breast;
4. Uncontrolled hypertension ( systolic ≥140 mmHg or diastolic ≥90 mmHg despite antihypertensive therapy)；
5. Known hypersensitivity to any of the study drugs or excipients;
6. Known hereditary or acquired bleeding and thrombotic tendencies (e.g. hemophiliacs, coagulation disorders, thrombocytopenia, etc.);
7. Congenital or acquired immune deficiency (e.g. HIV infected)