Single-Center CyTOF and Viral Imprinting Study in Postoperative Multiple Pulmonary Nodules

Inclusion Criteria: * Age 18 years or older, any sex. Primary pulmonary nodule has been surgically resected, with residual multiple pulmonary nodules or a need for pulmonary nodule-related routine postoperative follow-up. Planned routine postoperative follow-up at a participating center and able to provide a research blood sample together with routine blood draw when clinically available. Able to understand the study and willing to provide written informed consent before research blood sample collection. Exclusion Criteria: * Investigator judges that the participant is unsuitable for additional small-volume blood collection, such as severe anemia, obvious coagulation abnormality, recent severe bleeding, or high risk of severe vasovagal reaction. Acute severe infection, acute major organ dysfunction, or other condition that may substantially affect peripheral immune status and makes study participation unsuitable. Current strong immunosuppressive therapy that may substantially affect peripheral immune status and cannot be adequately recorded or adjusted for in analysis. Unable to complete informed consent or explicitly refuses use of research blood samples and related data for this study. Any other condition that, in the investigator's judgment, makes participation inappropriate.