- Loads of new content
- Epic space cowboy revenge story
- New game-mode Gambit
- New Weapon system
- More updates in the upcoming months
Forsaken Patch Notes
https://www.bungie.net/en/News/Article/47197
Detailed explanation of the new weapons system
https://kotaku.com/destiny-2-s-weapon-system-is-now-drastically-different-1828669413