Moving on sloped terrains poses challenges to robots in general. That applies to quadrupedal robots that are designed to mainly perform on flat surfaces. This video from RSL, explores the idea of dynamic trotting by quadrupedal robots on slopes. StarlETH, a fully autonomous, torque-controllable quadrupedal robot, was used to trot slopes up to 21″ thanks to estimation of the parameters of the terrain.
The robot adapts its body to the terrain to climb and come down. More information is available here.