Sun Wukong is five-times-immortal, because apparently each different method of achieving immortality has a loophole through which the immortal may still be killed. The loophole for one may be blocked by another. And if you're already immortal one way, you have time to do all the others, too.

This is why the divine court had to imprison him forever by pinning him down with a mountain heavier than he could lift. Execution wouldn't work.

There are quite a few books, movies, miniseries, and television shows covering this. The Monkey King is a cultural staple in China. Son Goku of Dragon Ball is also based on him. Loosely.