It will increase the amount of contacts you can have. Excavate your base (which you should constantly be doing anyway) and get some engineers working on it pronto. It’s highly recommended that once you can build this facility, you do. This is where the Resistance Comms Facility comes in. But what about when there are missions that are locked far away? The Avatar Project is booming away constantly, so you’re going to want to move fast to make contact. Since in the beginning missions will be near your HQ, you’re likely going to use these in the surrounding area. To start with you’ll only be able to make three contacts.
More importantly, it’s how you’ll reach certain missions that are initially locked until you make contact with a nearby Resistance group.
Doing this opens up your area of command and allows for even more resources to be added onto your income. You can see the different Resistance groups that you can make contact with all around the world. This is the main source of missions, objectives, and the Black Market.
When you go to the bridge on your base, you’re able to see the world map through the bridge. XCOM 2 will have you Commandeering an army of humans against the alien threat on Earth.