Tomlin could always be traded back to Tampa where it all began
Mike Tomlin had plenty of his formative years as an NFL coach in Tampa Bay with the Buccaneers. He was their secondary coach before finding promotion elsewhere. I'm sure both he and his family would love to go back to Tampa and move to Florida.
It could make sense as the Bucs seem likely to move on from Todd Bowles after this year. If word comes out that Tomlin is available via trade then many teams like would come calling. The Steelers could get some quality compensation from them too.
Pittsburgh makes a great trade here even though they do give up on some of their draft picks gained. They are still able to get a first this year and a third this draft too. But they also get a solid starting safety with Antione Winfield Jr.
Tomlin would be secure in Tampa and has pieces to work with down there. One would imagine he'd have to entertain that idea and so would the black and gold. Tampa also gets a solid return here with a couple of picks going back their way. This would make a lot of sense for both sides and the Bucs have a past with making trades at their top coaching job in the past.