PDCD1 and small cell lung carcinoma: PD-1/PD-L1 inhibitors + chemotherapy have a magnificent efficacy, which can be used in upper gastrointestinal malignancies, triple-negative breast cancer, NSCLC, SCLC, and other cancers (Paz-Ares et al., 2018; Cortes et al., 2020; Zhang et al., 2020; Janjigian et al., 2021).