https://www.gamespot.com/articles/e3-2018-cyberpunk-2077s-trailer-gave-away-witcher-/1100-6459622/

Microsoft's E3 2018 presentation finally debuted the first look at CD Projekt Red's upcoming game Cyberpunk 2077 with a trailer. But eagle-eyed viewers noticed a little Easter egg in the show, and received a free critically acclaimed game as a result.

Just as Microsoft's conference was ending, it was "hacked" by Cyberpunk to show one more trailer. The red DOS prompts that kicked off the takeover were familiar enough, but then they began to stream a series of codes rapid-fire. Some viewers noticed these 25-digit codes looked an awful lot like Xbox redemption codes, and promptly entered them. The ingenuity was rewarded with The Witcher 3: Wild Hunt GOTY edition.