CD274 and small cell lung carcinoma: In the phase II study of olaparib combined with durvalumab in the treatment of relapsed SCLC, Anish Tho et al. (Thomas, et al. 2019) collected pretreatment and on-treatment (2–4 weeks after treatment) tumor tissue biopsy specimens from the same location to evaluate the dynamic changes of T cell infiltration and PD-L1 expression.