Black Ops 2 multiplayer perks give you a variety of different enhancements, thus enabling you to customize your classes even further. Unlike in previous Call of Duty games, you can choose a total of 6 perks, but this limits the amount of customization you can do for your class. You can also opt-out and choose no perks from the Black Ops 2 perks list, and instead focus more on equipment and weapon attachments.
By default you can choose 3 perks for your class, one from each slot - with Wildcards you can choose one extra perk per slot for a total of 6 perks. Doing so, however, uses all your Wildcards and also takes 3 + 3 + 3 allocation points, which leaves you with only one weapon without attachments and no equipment.
Perks in BO2 don't affect your weapons stats; instead you'll have to use attachments to achieve, for example, better accuracy or deeper bullet penetration.
There are no Pro Perks in Black Ops II multiplayer.
Perk Slot 1
Allows you to move faster than normal. You also take no damage from falling.
You take less explosive damage, which allows you to survive (at full health) most explosive weapons that are used directly against you.
AI-controlled air support Scorestreaks can't detect you. Some air support Scorestreaks can be player-controlled at anytime, which means they are still able to attack you if the AI is overridden.
Allows you to earn bonus points for each action you take, which in turn earns you Scorestreak rewards faster. For example, capturing an enemy flag gives you 200 points, but with Hardline you get 250 points.
Enemy UAV's can't detect you while moving, but if you stop, you'll show up on the enemy radar.
Perk Slot 2
This perk makes you immune to enemy Counter UAV's and EMPs, which is pretty much the same as the Assassin Pro perk from Modern Warfare 3. While the EMP doesn't affect you, you still can't call in Scorestreak rewards.
Allows you to replenish your ammo, equipment and grenades from enemies that weren't killed with explosives. Killed enemies leave Scavenger bags that can be picked up.
Makes you invisible to enemy targeting systems, which include equipment such as the Dual Band, Target Finder, Sensor Grenade, and MMS. Enemy player-controlled air support Scorestreak rewards also can't target you normally.
Allows you to swap your weapons faster than normal - equipment and grenades can also be used faster. You can also safely throw back enemy grenades.
With this perk you flinch less when shot by the enemy.
Perk Slot 3
Makes you climb ladders and mantle over obstacles, such as gates, 50% faster than normal. You can also aim faster after sprinting and recover quicker from melee strikes.
Allows you to see all enemy equipment glow red through walls. This perk also delays enemy explosives that were triggered by you.
You can also booby trap Care Packages or re-roll the Care Packages content and hope that it contains something better.
Makes you more silent by reducing the sound made by your footsteps, jumps, and falls.
Allows you to sprint 2x longer than normal, which gains you a significant field advantage. Extreme Conditioning makes a return in the new Ghosts Perks system, but it now gives the player unlimited sprint.
Makes you more immune to Flash and Concussion grenades, including Shock Charges. This only reduces the effect and doesn't mitigate them completely.
Makes enemies at least 4x louder than normal. This allows you to hear their footsteps easier when they get closer to you. Works best with high quality headsets on the Xbox 360 and PlayStation 3.