Although Boba Fett returned to Star Wars in The Mandalorian season 2, the show had already established Din Djarin as his canon replacement. Introduced to the mainstream in The Empire Strikes Back, Boba Fett quickly became one of the most popular characters in the Star Wars original trilogy despite his short amount of screen time. The Star Wars Expanded Universe, now known as the “Legends” timeline, greatly expanded Boba Fett’s backstory and revealed that he survived falling into the sarlacc pit in Return of the Jedi. His long-awaited return in Star Wars canon was met with overwhelming excitement.
https://screenrant.com/star-wars-the-mandalorian-din-djarin-boba-fett-replacement/