Human microbes have been called "the second genome of humanity".On May 13,2016,the White House launched the National Microbiome Initiative (NMI), with an estimated investment of us $521 million, to elevate microbiome research to a national strategic status. The gut is the largest microecological environment in the human body. The research in the field of intestinal microbiome has become one of the most advanced and hot research directions in the scientific field of the world today. At present, more than 50 diseases have been found to be related to intestinal microbiome disorders. Pd-1 (programmed death receptor 1) is an important immunosuppressive molecule.It regulates the immune system and promotes tolerance by down-regulating the immune system's response to human cells and by suppressing T cell inflammatory activity. In the past, the research team and colleagues in related fields have found a strong correlation between Gut Microbiome and the efficacy of anti-PD-1 immunotherapy in cancer patients.This protects against autoimmune diseases, but it also prevents the immune system from killing cancer cells. As more and more scientific evidence shows that intervention of human intestinal flora may improve the efficacy of anti-PD-1 immunotherapy in tumor patients, intestinal flora, as the most effective way to intervene human intestinal flora, has been mentioned by many research institutions and international drug manufacturers in combination with anti-PD-1.Our previous study showed that the abundance of beneficial bacteria such as lactic acid bacteria, bifidobacteria and Akkermansia Muciniphila was significantly correlated with pD-1 inhibitor response, and regulating the intestinal flora content could improve the effect of PD-1 inhibitor on mouse tumors, indicating that microbial flora was involved in regulating cancer immunotherapy.

Inclusion Criteria:

• Karnofsky score ≥90 in patients receiving immunotherapy for non-small cell lung cancer at our cancer center

Exclusion Criteria:

• any immune system disease under high risk to antimicrobial agents such as Diabetes,infection disease or drug allergy to V9

The random assignment of patients was performed by Nanchang Medical University with a computer-generated random number code. Patients were randomly distributed in a 1:1 ratio to receive probiotics or a placebo (the block size was known only to the statistician). The drug was distributed and packaged in accordance with random numbers, and the documents stating the parameters, such as the blinding codes for the seeds of the random numbers, the block length, and the random numbers, were sealed in envelopes