CDK4 and acute lymphoblastic leukemia: Emerging agents targeting epigenetic regulators (menin inhibitors for KMT2A rearrangements), proteasome inhibitors, MEK inhibitors (for RAS pathway mutations common in both B-ALL and T-ALL), and CDK4/6 inhibitors (notably in T-ALL with NOTCH1-driven cyclin D3 overexpression) are expanding the therapeutic landscape [114,115,116,117,118,119].