It's been a very long time since I've played XCOM Apocolypse but there was a feature that I really enjoyed and hope to see some return in Phoenix Point.
In that game you were able to buy and sell weapons with the different factions. However the weapons that you researched would be entirely your own (until or if you sold said weapons to the other faction). After you sold your advanced weapons to another faction, you eventually saw that faction using the same weapons they bought from you.
This left you with a choice. Guard your intellectual property and the other factions were limited to their own designs. Sell or trade weapons to the faction and they gain new technology they can reverse engineer. BTW, this would be great working in both directions.
It also opens up different mission types where you must recover your stolen IP unless you want to be facing down your own researched tech in the future. You can also attempt to sell or trade said IP but trigger a mission allowing you to destroy their reverse engineering or decide to allow them to have it assuming your planning on an alliance with them.