CD19-B220+CD5+CD1d- Bregs, CD19+B220+CD5+CD1d+ B10 Bregs, and CD19+B220+CD27+IgD+ NSw MBCs demonstrate the most immunosuppressive phenotype based on IL-10 and PD-L1 expression in HCC/CaMIN mice. Here, CD19 is linked to hepatocellular carcinoma.