There is a very loyal and avid fanbase for anything that Rockstar Games touches. With the hype for Red Dead Redemption 2 extremely high, fans have done thorough analysis on the trailer to find more information about the game.
One user on NeoGAF went on a mission to try to track down who they believe is the Composer by comparing the music in the trailer to other pieces. The user believes the one who composed the music was two-time Academy Award winning composer Gustavo Santaolalla. The theory is based on music from an original score from Motorcycle Diaries titled Apertura.
Santaolalla won two Academy Awards for Best Score from the movies Babel and Brokeback Mountain. Santaolalla also composed the original score in The Last of Us as well as the popular Netflix series Making a Murderer.