Our experimental results indicated that there was no significant difference in the number of CD19+ B cells between AML patients and HDs in bone marrow or peripheral blood but that the CD19+ B cells from AML patients expressed more PD‐L1 than HDs (BM, p < 0.001; PB, p = 0.001) before treatment. The gene discussed is CD19; the disease is acute myeloid leukemia.