IDO1 and acute myeloid leukemia: While clinical trials of IDO inhibitors in patients with solid cancers, although well-tolerated, have been dismissed given their unclear benefit (Jung et al., 2019; Long et al., 2019; Reardon et al., 2020), these drugs have been found promising for myelodysplastic syndrome (Komrokji et al., 2019), and a specific trial for AML is ongoing (NCT02835729) (Wells et al., 2021), opening new perspectives for its exploitation in hematological cancers.