‘The Book of Boba Fett’ is ‘The Mandalorian’ “Season 2.5”; Mando Season 3 to Start Filming Late 2021/Early 2022
https://www.starwarsnewsnet.com/2021/06/boba-fett-wraps-obi-wan-kenobi-filming.html
“Collider has reported that The Book of Boba Fett has officially wrapped filming. The series is scheduled to debut this December on Disney Plus. It has been filmed on the same stage as The Mandalorian, and the first season is said to be a sort of stopgap between the second and third seasons of The Mandalorian, even referred to as “The Mandalorian Season 2.5″ by Collider‘s sources.”