Youtubers The Game Theorist (my son's favorite YouTube channel) did this short for them video on Overwatch. I thought it was going to go into the plot and the backstory of the game revealing clues that unwrap some sort of mystery or answer challenging questions because that's the normal thing they do. Instead this is more of a brief history of how one projects failure at Blizzard led to the creation of Overwatch. There's a bit too much OVERWATCH IS THE BIGGEST SHINIEST STAR IN GAMING RIGHT NOW sort of hyperbole going on but it's still interesting to hear about this project Titan that failed pretty hard. Blizzard isn't exactly known for churning out a bunch of clunkers so like I said, it makes for an interesting story.
Also if you're still not sure what Overwatch really is and what the appeal is they do a pretty good job describing it's appeal and where it really innovates in a genre that feels pretty oversaturated.