With or without The Collector, Guardians of the Galaxy Vol. 2 arrives in theaters on May 5, 2017, and Benicio del Toro will appear that following December in Star Wars: Episode VIII.
The Collector was introduced in Guardians of the Galaxy as the individual who hired Gamoa to steal the Orb, which he knew contained one of the Infinity Stones.
Given The Collector’s history with the Infinity Stones, it’s hard to imagine Marvel won’t do everything they can to bring del Toro in for Avengers: Infinity War.
As one of the oldest beings in the Marvel universe, The Collector is someone who can easily be expanded upon in the MCU.