Maleficent 3 is in the works at Disney.
According to Deadline, Linda Woolverton, who wrote the first two Maleficent movies, is now writing the third installment.

As of now, Disney hasn’t officially announced the film’s production. However, we can confirm that they will make an official announcement this year.
In the third installment, Angelina Jolie will return as Maleficent, and Elle Fanning is expected to reprise her role as Aurora.
Maleficent (2014) was directed by Robert Stromberg and written by Linda Woolverton. Angelina Jolie played Maleficent, and Elle Fanning played Aurora. The movie shows Maleficent’s past and how she became close to Aurora. It had a $180 million budget and earned $758.5 million.
Maleficent: Mistress of Evil (2019) was directed by Joachim Rønning. The story continues as Maleficent faces problems when Aurora gets engaged. Queen Ingrith (Michelle Pfeiffer) tries to separate them. The film had a $185 million budget and made $491.7 million, earning less than the first movie.
Maleficent 3 production details and release date are TBA (To Be Announced).
Source: Deadline