https://www.gameinformer.com/2018/11/06/heres-a-fun-secret-for-overwatchs-robotic-butler-bob

Overwatch players are just now getting to know Ashe, the latest hero who was just added to PTR on PC and will likely be added to full game in the weeks ahead. Early reports are that Ashe is a blast to play, but is a high-skill hero, especially for players who hope to shoot the dynamite out of the air. Basically, Pharah beware! Players are also learning that Ashe’s robotic butler B.O.B. may have a soft side when his gun arm isn’t blowing away the competition.

If Ashe waves at B.O.B., he will wave back. Blizzard even created two waving animations – one for if B.O.B. has his weapon drawn, and another if he’s standing idle. This a fun little discovery that I’m sure players will use in the pre-game lobby, and, you guessed it, to grief players after B.O.B. mows them down. Just a heads up that you’ll likely start seeing this animation as more players discover it.