CD4 and neoplasm: We conducted a preliminary retrospective study using perioperative indicators, pulmonary function indexes (forced vital capacity in 1 s, forced vital capacity, and maximal voluntary ventilation), immune function (CD3+, CD4+, and CD4+/CD8+ levels), and tumor marker levels (cancer embryonic antigen, carbohydrate antigen 50, and cytokeratin 19 fragment) to compare the efficacy of thoracoscopic lobectomy and segmentectomy for early-stage NSCLC.