This wildcard is unlocked at level 10. It does not see common use, as many players are good with just one perk 2, unless the player uses one perk on a consistent basis, yet needs another perk to go along with their class. A very popular combination that Perk 2 Greed provides is Fast Hands and Scavenger, which is a widespread strategy for C4 users. Cold-Blooded and Hard-Wired are used by some in an anti-Scorestreak class.
Perk 2 Greed returns in Call of Duty: Infinite Warfare. Unlike in earlier appearances, this Loadout Option does not have to be selected separately from the second perk, however selecting a second Tier 2 Perk cost 2 Allocation Points.