MCU: 10 Fascinating Facts Behind Captain America: The First Avenger (2011)
9. Wolverine & Magneto Almost Had Cameos
The First Avenger went through plenty of iterations before shooting finally started in 2010, with a 2008 script originally including cameo appearances by X-Men alums Wolverine and Magneto.
Given the movie's World War II setting, Logan would appear as a soldier and Erik Lensherr as a prisoner, but as is so often the case, rights issues got in the way.
As Captain America was ramping up to start principal photography, Fox was also prepping X-Men: First Class, and presumably in an attempt to "protect" the brand - this was early MCU after all - they refused to loan the characters out.
It's easy to sneer at Fox for making a bone-headed decision in retrospect - especially as Disney now owns Fox anyway - but given how risky a Captain America movie sounded on paper in 2010, you can't blame them too much here.
It would've been awesome, though.