This is an observational prospective bi-center study of 50 patients operated on advanced squamous cell carcinoma. The main aim is to investigate the efficacy of serum exosomal miRNA as a biomarker for predicting the therapeutic effect of immunotherapy combined with chemotherapy.

PD-L1 Testing in guiding patient selection for PD-1/PD-L1 inhibitor therapy in Lung Cancer exhibits insufficient sensitivity and efficacy. The investigators aimed to identify specific serum exosomal miRNA biomarkers that are highly sensitive and stable for predicting the therapeutic effect of immunotherapy combined with chemotherapy. So that the clinicians could use the biomarker to better stratify patients and select potential immunotherapy-beneficial subgroups before clinical decisions.

We plan to enroll 50 patients with advanced treatment-naïve squamous cell carcinoma and 10 healthy people in the present study. Peripheral blood from the plasma of 10 healthy individuals and 50 pulmonary squamous cell carcinoma (SCC) patients will be collected before first-line treatment and after 2 cycles of anti-PD-L1 immunotherapy combined with chemotherapy.

Firstly, exosomal miRNAs extracted from peripheral blood will be analyzed through high-throughput RNA sequencing to identify specific exosomal miRNAs.

Secondly, through analyzing the PFS and OS follow-up data of patients, they are divided into different subgroups. We explore the value of early predicting efficacy of exosome miRNA basing on sequencing results.

Thirdly, we compared the exo-miRNA biomarker with the value of PD-L1 expression in predicting the efficacy of immunotherapy.

Lastly, we suggest exo-miRNA combined with PD-L1 as a biomarker combination in predicting anti-PD-L1 immunotherapy efficacy to better select the potential benefit population suitable for immunotherapy.

Inclusion Criteria:

1. Histology or cytology confirmed patients with stage IV squamous cell carcinoma of IASLC TNM (8th edition);
2. Patients have not previously received first-line anti-tumor systemic therapy for advanced lung cancer;
3. At least one measurable lesion according to the irRECIST 1.1 standard;
4. Physical condition and organ function allow for systemic antitumor therapy, including standard chemotherapy and immunotherapy;
5. Age ≥ 18 years at the time of signing the informed consent form;
6. Estimated survival≥ 3 months;
7. Patients can follow the planned schedule and actively cooperate in returning to the hospital for regular clinical follow-up and necessary treatment;
8. It can provide the clinical data required for research and is willing to use the test data for further scientific research and commercial product development.

Exclusion Criteria:

1. Other malignancies within the last 5 years (except adequately treated carcinoma in situ and basal or squamous cell skin cancer);
2. The investigators judged that the patient also had other serious medical conditions that could affect follow-up and short-term survival;
3. Any other medical condition and social/psychological problems which the investigator determines that the patient is not suitable to participate in this study;
4. Contrast-enhanced MRI or contrast-enhanced CT for clinical follow-up is not acceptable;
5. Have an active or previous auto-immune disease that is likely to recur;
6. Other antineoplastic therapies were planned for the duration of the study.

Patients diagnosed as advanced lung squamous carcinoma by histopathology and be treated with anti-PD-L1 combined with chemotherapy