Minor spoilers for On the Road follow.
At the end of On the Road the narrator, Sal Paradise, is due to attend a Duke Ellington concert with his friend Remi Boncoeur. However, the situation is peculiar. Remi turns up in an expensive car - a Cadillac - but he himself is described as "sad" while his guests, Sal and his girlfriend, are "sad" because Sal's friend, Dean, has been barred from the concert by Remi (because Remi thinks he is an "idiot") and is leaving New York.
Both sadness and jazz music are important themes throughout the novel, not to mention Dean being the most central character, and I suspect there may be some significance in the way they come together in these final pages. It may be that Ellington himself is important, too, as few musicians are named during the narrative. What is it about this scene that ties these themes together as the novel ends?