CD274 and oral cavity squamous cell carcinoma: Ameloblastoma (AM), similar to oral squamous cell carcinoma (OSCC), is a typical epithelium-derived tumor with clinical characteristics of local invasiveness and a high recurrence rate.26 Research has confirmed that PD-L1 is widely expressed in OSCC tissues.27,28 On the one hand, membrane PD-L1 mediates immune evasion by binding to CD8 + T cells.