In Civilization 6, barbarians are a simple obstacle to understand: kill or be killed.
In the next update of the game, the barbarians get a complete overhaul that makes them more than just empty-headed golden pinatas. In the video below, developer Firaxis goes into detail about how it all works.
The February update, which is set for February 25 and is free for all players, adds the new Barbarian Clans game mode. It changes the way barbarians work in the game, adding six barbarian generations that can be found in or near different map conditions, each specializing in a different kind of unit. For example, you get the camps of the Hills Clan near hills and the Rover Clan near horses.
Clans can claim unique units and build great civilizations not found in that game. These tribes gather progress every turn to convert to a city-state. You can hinder their progress, or actually help the barbarians learn together and eventually become their Suzerain.
If you destroy a trunk, wipe it off the map as usual. But when you attack a clan, you earn some gold and destroy some of their progress to become a city-state. You can stop a clan from attacking your cities by paying bribes, and even hire a clan to add the strongest unit to your army.

If a clan kidnaps one of your units, you can get it back by paying a ransom. You can also spend gold to encourage a family to attack another civilization. The exchange of gold increases the clan’s progress in converting to a city-state.
Meanwhile, the February update adds the leader selection pool, allowing you to customize the pool of leaders that can be used in the game. There are also AI adjustments and balance changes (most AI adjustments focus on air units and air battles where they use air defenses and attack more frequently). Expect the patch notes along with the February 25 update.