It is CoD Points.
Gun Game - Everyone will start out with a pistol. With each kill a player will move up one level, which will grant them a new weapon. The game ends when a kill is achieved with all twenty tiers of weapons. However, if a player is knifed, they will move down a level. This mode was somewhat popularized by the Counter-Strike Series, where a similar game mode with the same name started. Yet In Counter-Strike the player starts with the best weapon, and it decreases to the least powerful guns, Treyarch did this so they can't have future issues of idea theft.
Sticks and Stones - All players spawn with a Crossbow, a Ballistic Knife, and a Tomahawk. Players can bankrupt one another of previous CP from kills with Tomahawk kills.
One in the Chamber - Each player starts out with a pistol with one bullet and their knife. One more bullet is gained with each kill. However, each player will only have three lives and if the bullet misses they only have their knife.
Sharpshooter - Every player will receive the same random weapon. After a set period of time (rumored to be anything between 45 seconds and 5 minutes), their current weapon will be cycled out for a new one. With each kill, a player will receive a perk and, eventually, a scoring multiplier.
Wager Match info from CoD Wiki with slight edits. :p
Sir Alex, the Ruby Knight of Everlasting Life