Payload is a gamemode where the objective is to escort the payload, a minecart, to a specfic location. There are currently 2 types of games: Attack/Defend (A/D) and Assault (Team vs Team)
Attack/Defend is a game Variant where one team, the attackers, is trying to escort the payload from one end of the map to the other end while the other team, the defenders, have to try and stop the payload in the time given.
Assault is a game Variant where the payload starts in the middle of the map and the teams have to escort it to the opposite end of the map.