Halo 4..

[SnesTea]

Dno said:

With more than 20 million copies of Halo 3 sold worldwide, I know it’s a no-brainer that the series would continue somehow.  It’s nice to get this sort of reassurance from a source who has never been wrong for us before.

 

I didn't know Halo 3 sold more copies than there have been Xbox 360's sold.