# Commutator of spin and linear momentum

More specifically, what is $[S_z, p^2]$? This came up in a time-evolution problem for $\hat{S}_z(t)$, knowing that that it commutes with the non-kinetic part of some Hamiltonian $\leftrightarrow [S_z, H]=[S_z, \frac{p^2}{2m}]$