Had a question about defense powers; are there some defense powers that are immune to Outwit? Granted some of the KC characters cannot have their abilities Outwitted unless by a character with KC. Is Invincible immune to Outwit? Clarification would be appreciated.

No standard power is inherently immune to being countered with Outwit (or any other method of countering powers.)

Hmm, perhaps I got confused when the one of the more experienced players told me that invincible was immune because the character had the cosmic keyword. Thank you for the clarification Vlad.

The cosmic keyword wouldn't do it either. Keywords don't have any inherent effects other than determining if your force is a themed team. They only matter when other effects reference them.
The Power Cosmic team ability would, though. (The Galactus-head symbol printed on the character's base.) I think that's probably what you meant (either that, or the player that taught you was confused.)

To add to vlad:

There's also Quintessence team, which is a giant purple Q on the team symbol. It prevents countering effects just like Power Cosmic does.

Fixed. As I frequently do, Outwitting abilities on Power Cosmic/Quintessence figs is legal and fun.

This is another fantastic example of why using shorthand to remember rules is a bad idea.

You will see tons of people who say "Power Cosmic gives you Willpower and doesn't allow you to be Outwitted."

That is a bad practice to do as it is not correct.

As RKJS mentions, you certainly can use Outwit on a Power Cosmic character, just not to counter powers. I've often used it to get rid of a PC guy's Flight or Carry.

Additionally, PC doesn't only prevent countering through the use of Outwit.
Take this CW SLOP Iron Man #002 for example:
Power Cosmic would prevent Iron Man from countering the power, but someone who thinks of PC in the shorthand above could easily think that it would not.

Except Earthbound, which is easy to forget.