Check out this post
#18 has the parts list for a 2019 Cherokee Limited...the TrailHawk not exactly the same install but very similar...probably need a different part number for the base plate (if you go with roadmaster)
If you are referring to the wiring harness to put the vehicle in 'tow mode', you don't need it on the 2019's with Active Drive II. You can tell you have Active Drive II if you have a small red recessed button to activate the transmission neutral (it will be just left of the shifter near the 4WD selector nob) and possibly a label on the tailgate. I'm pretty sure all TrailHawks have Active Drive II standard.
The only wiring you need to do is from the MH to the tail-lights. To be specific, there will be an umbilical from the MH to the toad, the wiring goes from toad connector to tail lights. That requires a kit that has the wire, connectors and diodes. Depending on the braking system you choose, you may need to tap into these wires to provide signals to a controller, so routing them appropriately is important.
I went to a couple of dealers when I bought my Jeep...not a one of the sales guys even knew what Active Drive II did, or how to identify a vehicle with it, even though most have a label on the rear tailgate and the red button is a dead giveaway. It's not even a surprise they couldn't find a part number...probably lucky they didn't find it.