While Overwatch itself does not have much in terms of cut-scenes or narrative elements, Blizzard has, however, given the game and its characters expansive legends through other ways, such as digital short films and comics. More recently, Blizzard has released a tale called "Bastet", which can be read here, this details the sexuality of one of the most popular characters in the game.
From Bastet's tale, it seems that Soldier: 76 is gay, and at one point was in a romantic relationship with a man named Vincent. Of course, it is possible that the soldier is bisexual or pansexual, but from now on the evidence indicates that he is mainly interested in men.
This revelation about Soldier: 76 seems to be obscuring other aspects of Bastet's story, such as the mission that Ana and Soldier are using, and the fact that the story also introduces a new skin for Ana. However, this is understandable, since that the Soldier's sexuality: 76 was not really touched in other Overwatch media, and seems to have caught many fans by surprise.
Of course, Soldier: 76 is not the only LGBT Overwatch character. In fact, Tracer was notoriously revealed as having a girlfriend in a holiday comic a few years ago, and the character Zarya is considered bisexual.
Since its inception, Overwatch has made an effort to be one of the most diverse video games that exists, and so far has fulfilled the promise, with LGBT characters like Soldier, Tracer and Zarya as proof of this. After the revelation of the latest Ashe hero as a playable character, however, some criticized Overwatch by not including any black playable female character. The lack of black female representation in the Overwatch The list was further examined when it came to light that both Ashe and Mercy were formerly regarded as women of color before receiving lighter skin tones after development.
With at least six more playable heroes in development, it's possible Overwatch will address that gap in your list in future updates. Meanwhile, fans can expect Blizzard to continue releasing new content that grows behind the scenes of the game's many heroes.
Overwatch is now out for PC, PS4 and Xbox One.