Objective To investigate the association between immune-related adverse events (irAEs) and postoperative pathological complete response (pCR) in patients with non-small cell lung cancer (NSCLC) receiving neoadjuvant immunotherapy combined with chemotherapy. MethodsThe clinical data of patients with stage Ⅱ-ⅢB NSCLC who received preoperative neoadjuvant immunotherapy combined with chemotherapy at the Department of Thoracic Surgery, The Third Affiliated Hospital of Kunming Medical University, from January 2023 to June 2025, were retrospectively collected. Based on the postoperative pathological evaluation of whether pCR was achieved, the patients were divided into two groups. The incidence, types, and severity of irAEs in both groups were recorded, and the association between irAEs and pCR was analyzed. ResultsA total of 131 patients were included, comprising 124 males and 7 females, with a mean age of (59.42±7.34) years. There were 65 patients in the pCR group, of whom 57 developed irAEs; and 66 patients in the non-pCR group, of whom 53 developed irAEs. The difference in overall irAEs incidence between the two groups was not statistically significant (P=0.249). Among the 110 patients who developed irAEs, subgroup analysis by irAE type showed that in the cutaneous toxicity group (n=66), 41 achieved pCR (P=0.008); and in the endocrine toxicity group (n=37), 26 achieved pCR (P=0.006). Both toxicities demonstrated a statistical association with pCR. Furthermore, multivariate logistic regression analysis revealed that cutaneous toxicity [OR=2.65, 95%CI (1.28, 5.50), P=0.009] and endocrine toxicity [OR=3.14, 95%CI (1.36, 7.26), P=0.007] were significantly associated with achieving pCR. Other types of irAEs showed no statistical significance with pCR (all P>0.05). The occurrence of grade 3 irAEs was not significantly associated with achieving pCR (P=0.611), and no grade 4-5 irAEs were observed. ConclusionDuring neoadjuvant immunotherapy combined with chemotherapy, the occurrence of cutaneous and endocrine toxicities is associated with a higher pCR rate.