Human Extraction is a mission type first introduced for the Post-Season 5 finale, and used again during the Main Season 6 Finale.
The Humans must reach and defend a single "Evacuation Zone" somewhere on the map. When they have held the point for a certain amount of time, they may call in for extraction via Walkie Talkie, and wait for the "Extraction Vehicle" to arrive. When the "Extraction Vehicle" arrives, up to 5 humans may "board" the vehicle and be "Evacuated" from the game. At this point, the players are considered to have "Survived," but they are allowed to come back in the game and play as Zombies if they so choose. The "Extraction Vehicle" can return multiple times, for as long as there are Humans willing to extract.
Unlike traditional missions, Human Extraction has a non-binary win condition. Full "completion" of this mission type is not possible; instead, success is measured by the number of humans that are extracted successfully.