This study is testing a new combination of drugs to treat certain blood cancers in young patients. The cancers being studied are called acute myeloid leukemia (AML) and acute leukemia of ambiguous lineage (ALAL). In some cases, these cancers don't respond to treatment or come back after treatment. The drugs being tested are revumenib, azacitidine, and venetoclax. Revumenib is the new drug we're trying with the other two.

Participants will receive different doses of these drugs to find the safest and most effective amount. If a patient benefits from just revumenib, they may continue it with their doctor's approval. After a transplant, the treatment plan might change based on the patient's needs.

• The study is for patients aged 1-30 years with specific types of leukemia.
• Participants can't be pregnant or have certain other medical conditions.
• The study involves taking specific anti-fungal drugs before starting treatment.