The phrase "influential pioneer" refers to a person who has had a powerful impact and is considered a trailblazer or leader in their field or area of expertise. Full definition
«An immersive exhibition, Peter Campus — Video ergo sum, on view at Jeu de Paume, Paris until May 28, 2017 is the first solo exhibition dedicated to American artist Peter Campus (born 1937, New York), one of the most influential pioneers of video art whose seminal work has inspired generations of artists.» (cristintierney.com)
Bochner — who has produced paintings, installations, and photography — is noted to be one of the most influential pioneers of Conceptual art, and the organizer of the first Conceptual art exhibition in 1966. (artsy.net)
The outpouring of grief from the loss of two of the most influential pioneers in music, Prince and David Bowie still resonates, leaving a void that will never be filled. (eastcityart.com)