In this talk, I will discuss the perturbative description of transverse-momentum-dependent parton dynamics in nuclear matter, using low-transverse-momentum Drell–Yan production as a concrete example. I will first introduce the relevant effective-theory modes and develop the power counting associated with Glauber interactions, the nuclear path length, and the medium-generated transverse-momentum and formation-time scales. I will then describe the one-loop calculation of the TMD splitting functions at the first nontrivial order in opacity, corresponding to two insertions of the Glauber interaction. The calculation reveals new collinear and rapidity divergences associated with radiation and forward scattering in the nuclear medium. I will focus on how consistency among the collinear, soft, and nuclear sectors modifies the rapidity renormalization-group evolution. The resulting evolution governs radiative corrections to the forward-scattering kernel and generates additional transverse-momentum broadening as the energetic parton propagates through the nucleus.