Pathological examination of the pleural effusion cells revealed malignant tumor cells, and subsequent gene analysis indicated epidermal growth factor receptor/anaplastic lymphoma kinase-negative (3D Med/NGS), PD-L1-positive rate of 50% (Ventana/sp263 Kit), tumor mutation burden 27.42 muts/mb (3D Med/NGS), and microsatellite stable (3D Med/NGS). The gene discussed is EGFR; the disease is neoplasm.