https://www.cbssports.com/nfl/news/sacking-father-time-elite-pass-rushers-productive-into-their-30s/
All-time greats seem to be able to keep up production through 35ish, and then there are the crazy exceptions of Bruce Smith and Reggie White who were monsters until almost 40.
CJ is going to decline, but there is a very realistic chance he could prove to be very productive for another full contract in AZ. I certainly would not trade him right now, I would look to extend him for 2-3 years and add another legit pass rusher on the other side.
If this mock had us trading CJ for #3 and getting Chase Young, I suppose you could make an argument...but I still would take the proven sack production.
If I was the Cards I would try to extend CJ to line up with KM's rookie deal. By then he will be 34, and it would make a lot more sense for us to move on. I would fully expect him to pick up another 50+ sacks in that time though!
Trade back to #12....draft Chaisson on the opposite side. Trade Peterson for #25 and pick someone that slides. Get an extra 2nd next year.
If Chaisson pans out, having 2 elite edge rushers would probably be more impactful than having PP21.