Confirmed Perks (not all of them are listed)

Start - Marathon: Unlimited sprint
Marathon Pro: Climb obstacles faster - Sprint 26 miles with Marathon
Start - Sleight of Hand: Faster reloading
Sleight of Hand Pro: Faster aiming down the sights - Get 120 kills with Sleight of Hand
Lv. 13 - Scavenger: Resupply from dead enemies
Scavenger Pro: Extra magazines - Resupply 100 times while using Scavenger (replacement for Bandolier)
Lv. 21 - Bling: Two primary weapon attachments
Bling Pro: Two secondary weapon attachments - Get 200 kills using a weapon with 2 attachments
Lv. 45 - One Man Army: Swap classes at any time; switch takes five seconds and replaces secondary weapon
One Man Army Pro: Swap classes faster - Get 120 kills using One Man Army
Perk 2 Start - Stopping Power: Increased bullet damage
Stopping Power Pro: Extra damage against enemy vehicles (helicopters, AC-130s, etc.) - Get 250 kills using Stopping Power
Start - Lightweight: Move faster
Lightweight Pro: Quicker aim after sprinting - Sprint 30 miles using Lightweight
Lv. 9 - Hardline: Kill Streaks require one less kill
Hardline Pro: Death Streaks require one less death - Get 40 killstreaks while using Hardline
Lv. 25 - Cold-Blooded: Undetectable by UAVs, air support, sentries and thermal
Cold-Blooded Pro: No red crosshair or name when targeted - Destroy 40 enemy killstreak rewards using Cold Blooded
Lv. 33 - Danger Close: Increased explosive weapons damage (replacement for Sonic Boom or Fireworks)
Danger Close Pro: Extra air support damage - Get 100 kills with explosives while using Danger Close
Perk 3 Start - Commando: Increased melee distance
Commando Pro: No fall damage - Get 20 melee kills while using Commando
Start - Steady Aim: Increased hip-fire accuracy
Steady Aim Pro: Longer hold-breath duration - Get 80 hipfire kills using Steady Aim (replacement for Iron Lungs)
Lv. 17 - Scrambler: Jams enemy radar near the player
Scrambler Pro: Delay enemy claymore explosions - Get 50 close range kills using Scrambler
Lv. 28 - Ninja: Invisible to Heartbeat Sensor
Ninja Pro: Footsteps are silent - Get 50 close range kills using Ninja (replacement for Dead Silence)
Lv. 37 - SitRep: Detect enemy explosives and Tactical Insertions (replacement for Bomb Squad)
SitRep Pro: Louder enemy footsteps - Destroy 120 enemy devices using SitRep
Lv. 41 - Last Stand: - - -
Last Stand Pro: Allows crawling and equipment - Acquisition Requirements Unknown