Ultimately, the patient was diagnosed as LS-SCLC (T2bN1M0 IIB) according to the 8th edition lung cancer stage classification from American Joint Committee on Cancer, Union for International Cancer Control and International Association for the Study of Lung Cancer.[21] Genetic testing indicated that programmed cell death ligand 1 was negative (tumor cell proportion score <1%, combined positive score <1), tumor mutation burden was low (5.03 Muts/Mb), and microsatellite was stable. This evidence concerns the gene CD274 and neoplasm.