As Florida Governor Ron DeSantis kicks off his presidential campaign in Iowa, former President Donald Trump is making the rounds in the key primary state too. CNN Political Director David Chalian explains how DeSantis has taken on Trump on the campaign trail. This comes as the GOP field of candidates continues to grow, with former Vice President Mike Pence, former New Jersey Governor Chris Christie, and North Dakota Governor Doug Burgum expected to make formal announcements next week.To learn more about how CNN protects listener privacy, visit cnn.com/privacy