However, PD-1/PD-L1 inhibitors failed to demonstrate significant efficacy in maintenance therapy and second-line treatment after first-line treatment of ES-SCLC (Pujol et al. 2019; Owonikoko et al. 2019; Spigel et al. 2021; Goldman et al. 2018; Gadgeel et al. 2018). Here, CD274 is linked to small cell lung carcinoma.