Sixteen teams of two go in. Only one team survives. This is Survivor GameZ, a "last man-standing" deathmatch tournament that happens in DayZ every month.
This weekend, the "finals" for the event were held, and they're definitely worth a watch -- months of invitationals have led up to it. If you haven't been keeping up with Survivor GameZ, basically, it takes top YouTubers and Twitch streamers, and forces them to take each other out in a brutal event. Of course, in addition to worrying about other players, contestants have to deal with zombies, supplies, weapons, and the map itself -- it's very intense.
It basically turns DayZ into an eSport of sorts, complete with prizes, casters, and viewers. Before the actual "match" starts, teams write storylines to explain the different phases, and competitors are expected to, well, entertain instead of just playing it safe. All of this comes together to make an amazing event where players fight each other for survival.
Here are the participants:
You can read more about the rules here, or the history of the event here. Otherwise -- start the Twitch vid in this post at around the 47-minute mark. Everything before that is interviews with the creators, as well as some backstory, which you can certainly watch, but they aren't the meat of the event.