He was the only adult charged in the case along with three who were juveniles at the time of the crime, including a then-15-year-old gunman. All have already reached separate deals.
An email sent to Walker's lawyers seeking comment was not immediately answered.
He was accused of leading the group to the rented mansion where the 20-year-old New York rapper Pop Smoke, whose legal name was Bashar Barakah Jackson, was killed on Feb. 19, 2020, during what was to be a four-day trip to Los Angeles. A 911 call from a friend of someone in the house reported armed intruders inside, police said.
The robbers knew the address because a day earlier, Pop Smoke had posted a photograph on social media of a gift bag he had received and the address was on a label, authorities said.
The rapper was in the shower when masked robbers confronted him. During a struggle, the 15-year-old, pistol-whipped him and shot him three times in the back, according to court testimony.
The attackers stole his diamond-studded Rolex watch and sold it for $2,000, a detective testified.
Born and raised in Brooklyn, Pop Smoke arrived on the hip-hop scene in 2018 and broke out with “Welcome to the Party” an anthem with boasts about shootings, killings and drugs that became a huge sensation, and prompted Nicki Minaj to drop a verse on a remix.
He had several other hits, including the album “Shoot for the Stars Aim for the Moon,” which was released posthumously.