The third-generation thermodynamic database that adopts the physics-based models over a wide temperature range is being developed in an attempt to increase the predictability and reliability of the CALPHAD (Calculation of Phase Diagrams) method. As a case study, this work used the new CALPHAD models to reoptimize Cr, Ni, and the Cr–Ni system. For pure elements, the Gibbs free energy of solid phases was described by a model considering various physical contributions, and the amorphous and liquid phases were described together by the two-state model. For Cr–Ni solution phases, thermodynamic modeling of the magnetic phase diagram was supported by ab initio calculations. This work demonstrated the way of performing thermodynamic assessment using the third-generation Gibbs free energy functions with the improved description of magnetic properties.