The magnetic DFT (BDFT) formulation of Grayce and Harris requires functionals of the form E(v; B) and F(ρ; B), which simplifies numerical implementation and avoids an explicit functional dependence on j p , at the cost of some degree of universality. Could the simplifications outweigh the loss of universality in practical implementations? Another alternative would be to consider the coupling of internal magnetic fields with the external field via a Maxwell-Kohn-Sham approach, which does feature a Hohenberg-Kohn result for the total current density. Such an extension may be important in strong-field time-dependent light-matter interactions 650 and leads to a more appealing functional dependence on the total current density, rather than only on its paramagnetic component. Finally, we mention linear-vectorpotential DFT (LDFT), a simplified formulation of CDFT suitable for uniform magnetic fields. Given recent strides in better understanding the theoretical foundations of CDFT, and the construction of several practical implementations, addressing these challenges should lead to further progress and improvements in the accuracy of magnetic response properties with DFAs.