The hero shooter genre has a variety of characters to choose from, all with different abilities. But Concord has a unique mechanic that determines which characters you can play in a match.
Concord Pro Overview – Altium Academy
In Concord, your game doesn’t really start when you queue up for a match. Once you level up, you can create your own Crews that you take with you to a match to earn various bonuses and have fun.
Here's an explanation of Crews and the Crew Builder mechanic in Concord.
In Concord, a Crew is essentially a group of Freegunners that players can choose from in each match. This affects which players you can choose from in the Freegunner Select screen, both before and during a match.