New Adjuvant Treatment of Locally Advanced Resectable Gastric Cancer With Carelizumab and XELOX

Inclusion Criteria: * Sign the written informed consent before implementing any test related process * Endoscopic or enhanced CT /MRI scanning (combined with ultrasonic gastroscopy and diagnostic laparoscopic exploration if necessary) cTNM was diagnosed as cT3-4aN1-3M0, and the investigator assessed that the lesion was resectable; * Have not received systematic treatment for current diseases in the past, including surgical treatment, anti-tumor radiotherapy and chemotherapy /immunotherapy; * Patients who agree to receive radical surgical treatment and have no surgical contraindication as judged by the surgeon * ECOG score 0-1; * The expected survival time is more than 6 months; * Female subjects of childbearing age should receive urine or serum pregnancy test within 3 days before receiving the first study drug (the first day of the first cycle) and the result is negative. If the urine pregnancy test result cannot be confirmed as negative, a blood pregnancy test is required. Women of non childbearing age are defined as those who have had at least one year after menopause, or who have undergone surgical sterilization or hysterectomy; * If there is a risk of pregnancy, all subjects (male or female) should use contraceptives with an annual failure rate of less than 1% during the whole treatment period until 120 days after the last study drug administration (or 180 days after the last chemotherapy drug administration) Exclusion Criteria: * Other malignant diseases (excluding skin basal cell carcinoma, skin squamous cell carcinoma, and /or carcinoma in situ after radical resection) diagnosed within 5 years before the first administration; * Known endoscopic signs of active hemorrhage of the lesion; * Currently participating in the intervention clinical research treatment, or receiving other research drugs or using research instruments within 4 weeks before the first administration; * Have received the following therapies in the past: anti PD-1, anti PD-L1 or anti PD-L2 drugs or drugs targeting another kind of stimulation or synergistic inhibition of T cell receptor (including but not limited to CTLA-4, OX-40, CD137, etc.); * Within 2 weeks before the first administration, he has received systematic systemic treatment with Chinese patent medicine with anti-tumor indications or drugs with immunomodulatory effects (including thymosin, interferon, interleukin, except for local use to control pleural effusion); * Active autoimmune diseases requiring systemic treatment (such as the use of disease relieving drugs, glucocorticoids or immunosuppressants) occurred within 2 years before the first administration. Alternative therapy (such as thyroxine, insulin or physiological glucocorticoid for adrenal or pituitary insufficiency) is not considered as systemic therapy; * The study was receiving systemic glucocorticoid treatment (excluding local glucocorticoids by nasal spray, inhalation or other means) or any other form of immunosuppressive therapy within 7 days before the first administration; * Known allogeneic organ transplantation (except corneal transplantation) or allogeneic hematopoietic stem cell transplantation; * People known to be allergic to the drugs used in this study; * People with multiple factors affecting capecitabine (such as inability to swallow and intestinal obstruction); * Before starting treatment, the patient has not fully recovered from the toxicity and/or complications caused by any intervention (i.e. ≤ Level 1 or reaching the baseline, excluding fatigue or hair loss); * Known history of human immunodeficiency virus (HIV) infection (i.e. HIV /2 antibody positive); * Untreated active hepatitis B ； * Active HCV infected subjects； * Live vaccine shall be inoculated within 30 days before the first administration (the first cycle, the first day); * Pregnant or lactating women; * Abnormal medical history or disease evidence, treatment or laboratory test value that may interfere with the test results, prevent the subject from participating in the study in the whole process, or other conditions that the researcher believes are not suitable for inclusion. The researcher believes that there are other potential risks that are not suitable for participation in the study.