[1] In 2006, Carlos Concepcion was arrested on felony drug charges for an illegal sale of cocaine.

[2] Subsequently, Concepcion filed a motion for sentence reduction due to Section 404(b) of the First Step Act.

He also argued that the district court should no longer consider him a career-offender under the 2018 Federal Sentencing Guidelines, since one of his conviction was previously vacated.

[2] The court granted certiorari on September 30, 2021, and heard oral arguments on January 19, 2022.

On June 27, 2022, the Supreme Court reversed the First Circuit's ruling in a 5–4 vote and held that the "First Step Act allows district courts to consider intervening changes of law or fact in exercising their discretion to reduce a sentence.