CD274 and cancer: There are many therapeutic drugs targeting MUC1 and PD-L1, such as MUC1-based cancer vaccines including mRNA vaccine [16], DNA vaccine, viral vaccine, DC vaccine [17] and glycopeptide vaccine, and there are many anti-PD-L1 monoclonal antibodies, such as Atezolizumab, Avelumab and Duravulumab [38,39].