Fermilab’s High Field Magnet (HFM) program (also a part of the National GARD program) is approaching the mature design phase of the 15 T Nb3Sn dipole model. The program is exploring the limits of Nb3Sn magnet technology with a possible target application in future proton-proton colliders. This effort is in synchronicity with Recommendation 24 of the P5 Committee and the HEPAP Accelerator R&D Subpanel Report.