BackgroundThe immune checkpoint inhibitors (ICIs) targeting anti-programmed death receptor 1 (PD-1) and its ligand (PD-L1) has shown promising value in resectable (stage I-IIIA) or potentially resectable (stage IIIB) non-small-cell lung cancer (NSCLC). However, the immune-related adverse events (irAEs) and tumor progression in neoadjuvant therapy are of great concern, which might result in surgical delay or failure to undergo resection. In addition, the association between the development of thyroid dysfunction and the cancer outcomes was controversial and highly concerned.Case presentationA 59-year-old male with NSCLC (squamous, IIIA) was received neoadjuvant immunotherapy in combination with chemotherapy before surgery. However, ICIs-related thyroid dysfunction occurred, and the patient experienced transient hyperthyroidism then transformed into hypothyroidism. Moreover, the patient suffered from tumor progression and was unable to undergo resection. He refused immunotherapy and was given chemotherapy for the subsequent treatment.ConclusionsWe presented the case of ICIs-related thyroid dysfunction and failure to undergo resection because of poor efficacy to elucidate clinical features of irAEs and tumor progression in the neoadjuvant immunotherapy, so as to timely and properly monitor the efficacy and safety of neoadjuvant immunotherapy in resectable NSCLC patients in clinical practice. Our case also demonstrated that the development of ICIs-related thyroid dysfunction might not predict the good efficacy of ICIs in NSCLC.