Diagnostic Biomarkers for Checkpoint Inhibitor-related Pneumonitis

Inclusion Criteria: 1. Patients with a pathological diagnosis of lung cancer; 2. The subject has received at least one course of immune checkpoint inhibitor treatment; 3. Capable of understanding and voluntarily signing an informed consent form. For the CIP group, the following additional criteria must be met: 4. Highly suspected of having checkpoint inhibitor pneumonitis based on radiological abnormalities and/or pulmonary symptoms (including fever, cough, and dyspnea). For the Control group, the following additional criteria must be met: 5. Has had no clinical symptoms or radiographic evidence suggestive of pneumonitis at enrollment or prior to enrollment. Exclusion Criteria: 1. Pulmonary lesions were definitively diagnosed as tumor progression, bacterial pneumonia, or pulmonary edema; 2. Incomplete or missing follow-up data.