This is a live performance of the song "I Lied To You" written by Raphael Saadiq and Lundwig Göransson and performed by Miles Caton, Göransson, and Jayme Lawson. It's so hard to believe that Miles Caton is only 20 years old and learned to play the guitar for this role with the way he performs. I love that you can feel the unabashed joy Caton and Göransson feel performing and Lawson and the audience feels listening and singing along.
My personal opinion is that while this live performance is amazing, this song must be experienced by watching the movie, preferably while it's still in theaters. The movie's visuals and context add so much to the performance and is truly the best way to experience the intended message. The scene in the movie where this song is perfomed legitimately brought me to tears, it was that moving.