The musical featuring the song 'TOMORROW' is ANNIE, a Broadway musical based on the comic strip Little Orphan ANNIE. It was first performed in 1977 and has since become one of the most popular musicals of all time. The show follows the story of an orphan girl named ANNIE who is taken in by billionaire Oliver Warbucks. The musical features many memorable songs, including 'TOMORROW', which is sung by ANNIE as she looks forward to a better future.