Loadout:
Assault Rifle
Pistol

Squaddie:
Run & Gun
Fire Pistol

Corporal:
Implacable
Bulletswarm (can take standard shots for 1 action)

Sergeant:
Hip Fire (A free rifle shot @ an aim penalty)
Walk Fire (A shot with extra aim but less crit, has a cooldown and uses 2 ammo)

Lieutenant:
Weapon Specialist (+1 dmg with rifles)
Cool Under Pressure (+10 aim and can crit on overwatch shots)

Captain:
Untouchable
Ever Vigilant

Major:
Extra Conditioning (Reduces the cooldown on run and gun by 1)
Guardian (50% chance to take another overwatch shot, can chain)

Colonel:
Rapid Fire
Saturation Fire

GTS:
Shake it Off (+25 dodge)