CD28 and hepatocellular carcinoma: Compared with control CD19-CD28-CAR-NK-92MI and CD19-CD28-4-1BB-CAR-NK-92MI cells, as described previously61, CD147-CAR-NK-92MI cells demonstrated significant cytotoxicity against several HCC cell lines, including SK-Hep1 and HepG2 (Fig. 1a, b), as well as Huh7 and HCO2 cell lines compared to parental NK-92MI cells (Supplementary Fig. 5).