Seven of the 10 commercials that generated the most media impressions during the 2017 MLB campaign did not debut until the last six weeks of the season. Hyundai’s “Duet,” which featured two Sonata drivers seeing each other at a stoplight singing Neil Diamond’s “Sweet Caroline,” represented the largest spend on a single ad by a brand, with $3.7 million. That spot ran 298 times during MLB telecasts.