If you sold your copy on 99gamers.com, you'd get 65-70 coins for it. You'd pay $2+ in shipping fees to exchange your ps4 copy for an xb1 copy.
Basically, you'd sell your ps4 copy, then use the coins you received to purchase an xb1 copy.
These are some of the cod aw listings that are up.
You could also check out reddit's game swap, but I've never used this.
I can't tell you much about it.