Yukon Denali towing
Had a 2008 Denali with 6.2 and HD tow pkg plus auto ride suspension and rated at 7900 lbs towing. Pulled a est. 5000 lb TT a number of times and in the NC Mountains. She worked on steep grades but she worked. Last summer, upgraded my TT to somewhere about 6500 lbs. Again, the Denali was up to the task. The key is the payload on the Denali; see the yellow label on the drivers side door jam. Mine was about 1350 lbs. That can be a limiting factor depending on your tongue weight, passengers and gear you carry in the truck. I upgraded to a GMC Sierra recently as we are going to do a cross country trip and 7900 lb Denali tow rating is too close to the anticipated 7000 lbs the loaded TT will probably weigh in at. Had to consider the mountains out west...high elevations and steep grades. The Sierra has a 1870 lb payload rating and can tow up to 11700 lbs..however, I will never try to pull that much.
Throw your Denali and TT specs on this forum. That will help others weigh in with different opinions. Be advised you may get a fair share of perspectives that suggest you need to have a 3/4 or 1 ton diesel truck to pull anything more then a little red wagon! Good luck.