(Jordan Strauss | Associated Press file photo) Musician Ahmir "Questlove" Thompson, seen here at the 2019 Academy Awards, is one of the people scheduled to appear in online panels and talks at the 2021 Sundance Film Festival. Thompson, best known as the leader of The Roots, is director of “Summer of Soul (… Or, When the Revolution Could Not Be Televised),” which has been selected for the festival's U.S. Documentary competition.