Lung cancer is the leading cancer in France in terms of mortality. The prognosis of the disease is closely correlated with the diagnostic stage and the majority of patients are diagnosed at a metastatic stage. The arrival of immunotherapy has made it possible to change the therapeutic paradigm by significantly improving the survival of metastatic patients. Despite this progress, only 20 to 30% of patients respond to immunotherapy. The search for predictive factors of response to or resistance to these drugs is of major importance for better patient selection. Among these factors, the intestinal microbiota appears to be closely correlated with the response to immunotherapy via the education of adaptive anticancer immunity. Thus, several bacterial species have been associated with patient survival or disease progression. Interestingly, the abundance of these same bacteria can be modulated by certain drugs co-prescribed with immunotherapy. These dysbiotic treatments or those leading to a significant modification of the composition of the intestinal microbiota could then modulate the response to immunotherapy and therefore patient survival. The objective of this study is therefore to objectify the impact of several therapeutic classes modifying the intestinal microbiota initiated in the 90 days preceding D1 of immunotherapy on the survival of patients with locally advanced (stage III-C) or metastatic (stage IV) non-small cell lung cancer (NSCLC)