Edit the config file:

UbisoftSplinter Cell Pandora Tomorrow offlinesystemSplinterCell2User.ini

and bind a code to a key:

F1=OPSAT
F2=Invisible
F3=Invincible
F4=ammo
F5=Savegame
F6=summon echeloningredient.estickyshocker
F7=summon echeloningredient.eringairfoilround
F8=Loadgame
F9=summon echeloningredient.efraggrenade
F10=summon echeloningredient.estickycamera
F11=summon echeloningredient.ediversioncamera
F12=summon echeloningredient.ecamerajammer

Or:
You need to open your SplinterCell2user.ini file. It is located in Ubisoft splintercellpandoratomorrowofflinesystem file. Open it with notepad and under Engine. Input choose an unbound key and one of the following codes after it. You can also use other unbound keys to input other codes as well. Now while in game press the bound key and your code will activate. Now be sure to bound another key to turn the code off. These codes are basically the same as SC1 put you have to bind them to key for them to work.

fly - floating 
playersonly - freeze enemies 
health - gives health 
invincible 1 - god mode 
invincible 0 - god mode off 
killpawns - kills all enemies 
ammo - more ammo 
ghost - no clip mode 
walk - no clip off 
invisible 1 - (you will not see Sam) Sam is invisible but enemies can still bump into him and start alerts. 
summon echeloningredient.eringairfoilround spawn airfoil round 
summon echeloningredient.edisposablepick - spawn disposable pick 
summon echeloningredient.eflashbang - spawn flashbang 
summon echeloningredient.efraggrenade - spawn frag grenade 
summon echeloningredient.esmokegrenade - spawn smoke grenade 
summon echeloningredient.estickycamera - spawn sticky camera 
summon echeloningredient.estickyshocker - spawn sticky shocker 
summon echeloningredient.ewallmine - spawn wallmine 
invisible 0 - turns off invisible 
playersonly 0 - unfreeze enemies