In this week’s Sunday Sitdown, Willie Geist goes fly fishing with former “Late Show” host David Letterman ahead of the premiere of the second season of his Netflix series, “My Next Guest Needs No Introduction.” Sporting a full beard, Letterman opens up about how his life has changed since no longer being on television every night. » Subscribe to TODAY: http://on.today.com/SubscribeToTODAY » Watch the latest from TODAY: http://bit.ly/LatestTODAY