We have formulated the de Sitter gauge theory of gravity which have Yang-Mills type Lagrangian in 5-Dim. Riemann spacetime.
At low energy, this SO(4,1) gauge symmetry is broken to Poincare symmetry in 4-Dim. Riemann spacetime.
Then the theory gives correct macroscopic phenomena because the Einstein action in 4-Dim. Riemann spacetime is generated from the symmetry broken action of Yang-Mills type.
In many respects, we expect that the SO(4,1) gauge theory in 5-Dim. Riemann spacetime may cure various problems in the traditional gravitational theory in 4-Dim. curved spacetime.