CD274 and head and neck squamous cell carcinoma: To examine whether PD‐L1 is involved in cisplatin resistance in HNSCC, expression of CD274 and PD‐L1 in the established cisplatin‐resistant HNSCC cells, CAL27cis and Detroit‐562cis, were shown significantly higher than the cisplatin sensitive cell lines by qRT‐PCR and WB (Figure 1F‐I).