Treatment of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) requires new therapy options, especially for patients uneligible for intense chemotherapy or with relapsed or refractory disease. CLEVER-1 is a myeloid checkpoint protein, which can be targeted with a therapeutic function blocking antibody, bexmarilimab. Bexmarilimab has shown clinical efficacy in different solid tumors. Here, we show preclinical data demonstrating expression of CLEVER-1 on immature malignant myeloid cells and their derivates in MDS and AML bone marrow samples and AML cell lines. Highest CLEVER-1 levels were observed in AML with monocytic differentiation. Ex vivo treatment of AML/MDS bone marrow samples with bexmarilimab led to an increase in antigen-presenting human leukocyte antigen DR isotype (HLA-DR) molecule expression. Combination of bexmarilimab with current standard-of-care (SoC) drugs, azacitidine and venetoclax, showed potential for HLA-DR induction and enhanced killing of leukemic cells, respectively. Our non-clinical findings support the feasibility of CLEVER-1 inhibition in AML/MDS to induce antigen presentating molecule expression and potentially, an anti-leukemic effect together with SoC. Therapeutic targeting of CLEVER-1 with bexmarilimab is currently undergoing clinical investigation in the BEXMAB trial (NCT05428969).