Pulmonary sarcomatoid carcinoma (PSC) is a rare form of poorly differentiated non-small-cell lung cancer that is prone to distant metastases. PSC is therapeutically challenging, with low sensitivity to conventional radiotherapy and a poor overall prognosis. The present study reported on the case of a 29-year-old male non-smoker diagnosed with both PSC and lung adenocarcinoma; the cancer had a complex etiology and rapidly metastasized after surgery. The patient presented with an EML4-ALK gene fusion in both tumors with high programmed death ligand-1 (PD-L1) expression. After initial treatment failure, Alectinib, Anlotinib and Tirelizumab were combined, which rapidly resolved the patient's symptoms and led to partial remission of disease at 6 weeks and effective control of the disease 7 months into the treatment. This case exemplifies the efficacy of combining targeted chemotherapy with immunotherapy for patients with PSC. Furthermore, this outcome suggests the usefulness of genetic testing and monitoring PD-L1 expression to identify patients with PSC who may be candidates likely to respond to this combined therapeutic regimen. The present study provides evidence of the success of a novel therapeutic strategy for patients with PSC.