It is a part of the category of the same name. It is the most basic game rule of the team based game modes: Two teams, red and blue, fight for the highest amount of kills. The match can be won by either reaching the kill limit, or by having the most kills when the time ends.
Three pilars can be found in the match, Health - Speed - Damage, and can be captured by standing near them; these pilars grant power boosts for the members of team that captures them. Capturing and securing these can take some time but are not mandatory to win the match.