Linkin Park has too much of a different style... I don't think their style of music would mix well with Creed's... for a song at least. As for touring together, again, it wouldn't make sense because of the two totally different styles of music. I'd bet that a majority of Linkin Park die-hard fans don't like Creed.
The things that I've loved the things that I've lost
The things I've held sacred that I've dropped
I won't lie no more you can bet
I don't want to learn what I'll need to forget
- Audioslave, "Doesn't Remind Me"