Sounds like front driver side underneath. Definitely not a belt issue. Squeaks Anytime the car has been sitting long enough to cool down.Difficult to say with such little information. What end of the car? What side of the car? Is it only on the first start of the day? Knowing things like that could lead to an answer.
Maybe the OP keeps running over squirrelsWow you are right but is the OP still having the same issue 2 years later? I mean the reply makes its seem so with the 2020 Rental from the dealer but the milage, now or 2 years ago. Again I am going to say now based on the year and the fact that the truck was new in 2018. I have a 2018 and the squeak they are speaking of isn’t normal on my truck, the only noise I get on a cold start is squeaking brake pads.
I'm starting to think it's your ears, something you carry with you...I thinks its "normal". My moms 20 acadia does it too. And the loaner i had from gmc as well.