  Recent theory progresses in (3+1)D dynamical descriptions of relativistic
nuclear collisions at finite baryon density are reviewed. Heavy-ion collisions
at different collision energies produce strongly coupled nuclear matter to
probe the phase structure of Quantum Chromodynamics (QCD). Dynamical frameworks
serve as a quantitative tool to study properties of hot QCD matter and map
collisions to the QCD phase diagram. Outstanding challenges are highlighted
when confronting theoretical models with the current and forthcoming
experimental measurements from the RHIC beam energy scan program.
