Call of duty black ops perks are split into 3 sections. Below is a list of the perks.
Perk 1
Lightweight
Standard: Allows you to move quicker through the map.
Pro: You can fall from a height without incurring any damage.
Scavenger
Standard: Resupply your ammo from enemies that have been killed. Unlike previous games you do not resupply your equipment.
Pro: Gives you double the amount of ammo from the start and also allows you to resupply your tactical grenades.
Ghost
Standard: Invisible to enemy Spy Planes and the Blackbird.
Pro: Invisible to enemy aircraft the attack dogs and sentry guns plus the enemy will not be able to see your name or a red crosshair when they are aiming at you.
Hardline
Standard: Gain killstreak rewards 1 kill earlier.
Pro: Gives you another go on the contents of a care package.
Flak Jacket
Standard: Additional explosives protection.
Pro: Allows you to reset the fuse of grenades so you can toss them back.
Perk 2
Hardened
Standard: Deeper impact on bullet penetration.
Pro: Deeper impact and more damage to enemy aircraft.
Scout
Standard: Allows you to hold your breath for longer, great for sniping.
Pro: Allows you to swap between your weapons quicker.
Steady Aim
Standard: Better chance of hitting your enemy and more accuracy when shooting from the hip.
Pro: Aim your gun quicker and recover from a knife lunge.
Sleight of Hand
Standard: Reload your weapon quicker.
Pro: Aim your gun quicker with guns that don’t have scopes on them.
Warlord
Standard: Allows you to add 2 attachments to your main weapon.
Pro: Allows you to have 1 extra lethal and tactical grenade from the start.
Perk 3
Marathon
Standard: Allows you to run for longer.
Pro: Allows you to run for an unlimited time.
Ninja
Standard: Move silently
Pro: + Louder enemy footsteps, makes you completely silent
Second Chance
Standard: Lets you pull out your pistol before dying so you can try and get back at your enemy.
Pro: Allows any of your team mates to revive you after being shot.
Hacker
Standard: Allows you to see where enemy equipment is.
Pro: Allows you to set a booby trap on an enemy care package and also change any enemy equipment to your own team.
Tactical Mask
Standard: Allows you to withstand the effect of a flash or concussion grenades.
Pro: Allows you to have a reduction in the effects of a gas or concussion grenade. It also shows where any enemies are that have been flashed or stunned.