CD274 and lung carcinoma: Therefore, we conducted a prospective observational study to assess the efficacy, safety, and prognostic factors of ICI retreatment after the failure of chemo-ICIs while focusing on the significance of the ICI sequence of anti-PD-1 and anti-PD-L1 therapies (North Japan Lung Cancer Group Trial: 1901 [NJLCG 1901]).