As of September 2019, the player count for Destiny 2 is approximately 8.2 million. This is down from the game's peak player count of 11 million, which it reached in December of 2017. However, Destiny 2 has seen a resurgence in popularity in recent months, thanks to the release of the game's third expansion, Forsaken.
As of July 2019, there are an estimated 8.2 million Destiny 2 players. This number has likely grown since then, as the game continues to be quite popular.