We already knew that Overwatch is a huge success. For example, Blizzard recently announced that the game has been played by over 30 million people . It should be clear that this means Overwatch was good for quite the cash-flow for Activision-Blizzard.
This has been evidenced by the financial results released by Activision-Blizzard over the first quarter of 2017. The US publisher is telling its shareholders that Overwatch has now delivered more than one billion dollars. These earnings are, of course, not only from initial sales, but also the lootboxes you can buy in-game, especially during seasonal events, for a lot of extra income.
Activision-Blizzard announces that Overwatch is the eighth franchise of its portfolio that has delivered more than one billion dollars.