Deadline, Paramount will air a Super Bowl TV spot for Transformers: The Last Knight at some point during the game. It was known that Paramount purchased 30 seconds of air time which is pegged at costing between $5 to $5.5 million but which movie was not revealed. Now the game plan is to air a spot for Ghost in the Shell before the game (so expensive but not $5M expensive) and The Last Knight during the game.
If I recall correctly, Age of Extinction Super Bowl ad ran in the third quarter and Dark of the Moon during the second so past behavior isn't much of a guide. The cost for the ad is due to the simple fact that the SuperBowl is consistently the most watch single event in the United States each year with and average of 100 million plus people watching the game resulting in ad revenue during the game (so not including before or after) that starts at a quarter of a billion dollars. It remains debatable if the companies that buy the ads get their money's worth but clearly Paramount believes it helps Transformers in each movie's quest to cross the billion dollar worldwide box office.