TQB2450 Plus Anlotinib Combined With Chemotherapy in the Treatment of Gastric or Gastroesophageal Junction Adenocarcinoma

"Initial treatment (6 cycles)：~1. TQB2450：1200 mg , Day 1 ivgtt ,once every 3 weeks~2. Anlotinib: 10 mg/day orally ，from days 1 to 14 in a 21-day cycle~3. Oxaliplatin: 130 mg / m2, Day 1 ivgtt ,once every 3 weeks~4. Capecitabine: 1000 mg / m2, orally, twice a day (once in the morning and once in the evening), from days 1 to 14 in a 21-day cycle Maintenance treatment：~1）TQB2450: 1200 mg , Day 1 ivgtt , once every 3 weeks 2）Anlotinib: 10 mg/day orally , from days 1 to 14 in a 21-day cycle"