Kong et al. recently reported a combination inhibition of JAK and MEK in controlling juvenile myelomonocytic leukemia (JMML) and the myeloproliferative variant of chronic myelomonocytic leukemia (MP-CMML) that prevented T-ALL development in NrasG12D/G12D mice [50]. Here, MAP2K7 is linked to juvenile myelomonocytic leukemia.