I'd start off by him taking the whole summer off. He'd just be posting tweets of different spots the WWE title was at.
His new music would hit near the end of the main event match at Survivor Series. Only for a shot of his name to be plastered saying "I'm Back. To Rule. The World. CM Punk."
Then for the next few weeks the same video plays only for him to truly show up at the Royal Rumble tossing John Cena out of the ring after Cena wins the Rumble and being crowned new WWE champion (which from MITB to Mania there was no champion). Thus setting up their feud for undisputed champion at Mania.