Evaluate the prognostic correlation between the neutrophil ratio and the ratio of CD4+/CD8+ T cells in patients with advanced non-small cell lung cancer (NSCLC) who receive immunotherapy combined with chemotherapy, with the aim of providing references for clinical treatment.

According to the content released in the Global Cancer Statistics Report 2022 (Global Cancer), lung cancer is the leading cause of cancer-related deaths worldwide. Traditional treatment methods such as surgery, radiotherapy, and chemotherapy have limitations in their curative effects. Immune checkpoint inhibitors (ICIs) have greatly changed the treatment landscape of non-small cell lung cancer (NSCLC). Although progress has been made in immunotherapy, the prediction of its efficacy relies on methods such as Tumor Mutational Burden (TMB) and the expression of PD-L1. Therefore, finding more effective treatment strategies and prognostic evaluation indicators has become a key task in lung cancer research. Relevant studies have delved into the prognostic and predictive values of inflammation-related peripheral blood biomarkers in NSCLC patients receiving immunotherapy. The Neutrophil-to-lymphocyte ratio (NLR) has emerged as a potential biomarker for cancer prognosis. However, lymphocyte subsets can be influenced by factors such as race, age, medications, gender, stress, physical activity, and lifestyle. In this study, CD4+/CD8+ T cells were selected to eliminate the influence of individual differences, and it is intended to investigate whether there is a prognostic correlation of CD4+/CD8+ T cells in the immunotherapy combined with chemotherapy for patients with advanced NSCLC.

Inclusion Criteria:

• (1)Inoperable stage III or IV NSCLC (AJCC 8th edition TNM staging) confirmed by pathological histology or cytology.(2)Received first - line immunotherapy (PD - 1/PD - L1 inhibitors) combined with chemotherapy, and driver genes are negative.(3)There is at least one measurable lesion in the lungs on CT imaging (RECIST 1.1).(4)Have complete clinical data.(5)The patient or the authorized family member gives informed consent.

Exclusion Criteria:

• (1)Have gene mutations such as EGFR/ALK/ROS1 and have not received standardized targeted therapy.(2)Have a second primary malignant tumor concurrently.(3)Have been infected or used antibiotics within 7 days before blood sampling.(4)Have severe abnormalities in the functions of organs such as the heart, liver, lungs, kidneys, and bone marrow.(5)Have other autoimmune diseases and endocrine and metabolic diseases concurrently.

Patients with advanced NSCLC who received immunotherapy combined with chemotherapy at Jiangxi Provincial Cancer Hospital