Looking online, we have this. Take home point is that whilst we have a temperature gradient of 30-35K / km on Earth, Mars may have a gradient of 6 - 10K / km. That makes geothermal energy very hard to do.
But it's worse than that. On Earth, you extract Geothermal energy by pumping water through rock formations that are already saturated with liquid water. The same paper shows that this won't be the case in the upper few km of the Martian crust. So extracting what warmth there is there would be harder.
As L.Dutch said, you could use the crust as a constant-temperature source for ground source heating/cooling, but actual geothermal energy is probably out of the question.