Chemotherapy based on intrapleural perfusion hyperthermia (IPH) can markedly improve the sensitivity of lung adenocarcinoma cells to anti-programmed cell death receptor 1 (PD1) antibody adjuvant chemotherapy and enhance the clinical response of a patient. In the present study, a unique case of a patient who failed to respond to immunotherapy combined with chemotherapy but achieved prolonged stable disease after treatment with IPH and subsequent sintilimab-based treatment, is reported. A 50-year-old Chinese female patient was admitted to a regional cancer hospital presenting with hemoptysis and persistent fever. The findings of computed tomography imaging and thoracic puncture tissue biopsy indicated a diagnosis of adenocarcinoma. The TNM and clinical stage were identified as cT2N3M0 and stage IIIB, respectively. Immunohistochemical tests showed the expression of programmed death-ligand 1 (PD-L1) with a tumor proportion score of 2%. No other classic genetic alterations were detected. Initially, sintilimab-based chemotherapy at 200 mg was administered, for three cycles from April 2020, and increased pleural effusion was observed on the left side. The best overall response (BOR) assessment of the local lesion was progressive disease. IPH combined with chemotherapy was then carried out from August to September 2020, after which the same course of sintilimab-based chemotherapy as aforementioned was provided from October 2020 to September 2023. The BOR evaluation results during the monotherapy courses were all judged as stable disease. Therefore, it was concluded that IPH can substantially improve the efficiency of anti-PD1 antibody-based therapy for lung adenocarcinoma.