Will a fig tree grow outdoors in Denver City. Will a pecan tree grow outdoors in Denver?
Denver County Colorado trees and shrubs
This source and others say cold-hardy figs can go to zone 5, which is what Denver is.
Selected varieties of pecan trees are said to be hardy to zone 5. Google this: "pecan tree hardiness" and you can see.
If possible, I would suggest getting your your tree stock from a nursery in a cold place, to be sure it is cold-hardy.
Best of luck.