While Fergie never commented on it herself, in a 2019 interview with Billboard, the Black Eyes Peas members' confirmed that Fergie had left the band to focus on her solo music career and to be a good mother to her son Axl.

What happened Fergie?

In September 2019, The Duchess singer announced that she had separated from her husband of eight years, Josh Duhamel. The two had been together since 2004 and even have a son named Axl. ... It's rumoured that Josh is the one who initiated the divorce and Fergie tried to keep it from happening for as long as she could.

Is Fergie going back to Black Eyed Peas?

She's featured with Ozuna on "Mamacita" and also appears on her own for "TONTA LOVE." When the Peas revealed this album, they also announced that Fergie was going to be stepping back for personal reasons. "We love her, and she's focusing on being a mom," will.i.am said in an interview with Billboard.