Totally depends on how much of an incline. TT’s can be leveled front to back, side to side. You may need to get some leveling blocks, boards, or add levelers to the TT. You also need some wheel chocks to keep the TT from rolling, and it’s a good idea to use them even on level ground. Don’t know about where you are but many localities have rules about parking RV’s on the street much less setting them up for temporary occupancy.
If you can get the TT “close” to level you should be fine for use. The fridge (standard RV fridge) is probably the most sensitive in operation in that if not fairly level, you can damage it by running it.