Here's the official Destiny 2 gameplay reveal trailer.
Destiny 2 will include a lot of quality of life improvements over the original game. It includes 4 planets, a new raid, looking for group, integration into the game, and bigger worldspaces with more content (including an area that is twice the size of the former biggest area).
Destiny 2 on PC will be available through the Blizzard Battlenet app.
Here's a full 9 minute gameplay reveal video that shows even more footage: