CD274 and type 2 diabetes mellitus: In addition to downregulation of PD‐L1 expression using RNAi technology, metformin (MET), a widely used small molecule drug for the treatment of type 2 diabetes, has also been reported to involve in endoplasmic‐reticulum degradation of PD‐L1.[164] Therefore, targeting delivery of MET to tumor cells and enhance its uptake may be a good alternative strategy to sensitize other therapy.