@Dagimir There will be hard world bosses, they may require raids to fight.
What you probably meant is will there be an instanced raids? Fractured MMO is not focusing on instances, it's focusing on open world, full loot open PvP, which could also include hard monsters that will require many people to defeat.
The only possible connection with instances would be asteroids, that will be proceduraly generated content. They could come in form of "classic raids", although we don't have many details yet on how they will work, so we don't know if an asteroid will allow everyone in who wants it, or will some asteroids allow only single group of people (raid) to enter. It's quite possible some of the asteroids will allow everyone in, and some might be designed as "classic raid" events.
We need to wait to get more info on that.