RecruitingPhase 2Drug trialThe Efficacy of Bevacizumab and Serplulimab Combined With Recombinant Mutant HumanTumor Necrosis Factor(rmhTNF-NC) in the Treatment of Malignant Ascites1. More than half of peritoneal metastases are from digestive tract. Peritoneal metastasis has poor prognosis, poor treatment response and limited means. 2. rmhTNF-NC or bevacizumab are effective in the treatment of malignant pleuroabdominal effusion. 3, There is increasing evidence that PD-1/PD-L1 inhibitors in combination with vascular endothelial growth factor receptor (VEGFR) inhibitors have a complementary mechanism of action: VEGF pathway inhibitors normalize blood vessels in tumors and promote immune cell maturation and infiltration, thus playing a synergistic role with ICIs. The strategy of systemic immunotherapy combined with antivascular therapy has been confirmed by several large phase III clinical trials such as IMbrave-150. Basic studies have confirmed that uncontrolled tumor vessels in peritoneal metastasis and malignant ascites microenvironment also play an important role in promoting disease progression. Therefore, this project intends to explore the treatment of malignant abdominal effusion by local intraperitoneal injection of bevacizumab and PD-1 on the basis of rmhTNF-NC