Another vast field that has grown rapidly in the past decade is the combination of densitybased embedding with correlated wavefunction methods. Novel developments include accounting for ever more sophisticated interactions, and the use of more and more accurate types of wavefunction methods. Libisch, Huang, and Carter have discussed theory and applications of embedded correlated wavefunction methods, making use of a densitybased embedding potential derived from potentially periodic environments . Another review by Carter and co-workers provided an overview of density-functional and potentialfunctional embedding . Different perspectives on wavefunction-in-DFT embedding have been discussed in Ref. . Here, we will review the developments in wavefunctionin-DFT embedding in Section 6.6. The accuracy of sDFT/FDE calculations in practice hinges on the approximations used for the non-additive kinetic-energy functional [Eq. ( )] and the corresponding potential [Eq. ( )]. Most commonly, decomposable approximations to the NAKE are employed, which are based on an approximate, explicitly density-dependent kinetic-energy density functional Ts [ρ], i.e.,