The MLB announced this morning in a press release that they are introducing a microphone for umpires to use when reviewing a call on the field. This is great news for both fans and players as the MLB attempts to become more interactive.
The MLB's move will greatly improve fans' awareness of what the umpires are reviewing. This will likely seem familiar to what the NFL does with their referees for official reviews.

"Major breakthrough for baseball fans. Starting next week MLB umpires will now use a microphone to announce replay review decisions to the crowd. NFL style. This is a welcome change and will help fans better understand the outcomes." - @ Sweeny Murti
What this means for MLB fans

Umpire commentary will greatly improve the overall fan experience. No longer will fans in the stands be confused or puzzled over what is being reviewed.
This is one of several announcements the league has made in regard to rule changes this offseason. Other notable rule changes for the upcoming season include impementation of the DH in the National League. No longer will pitchers hit for themselves, except Shohei Ohtani and others who are capable.
Other rule changes of note for the 2023 season include a shift ban, pitch clock, and larger bases.
"The union also permitted MLB to implement rule changes with 45 days notice, which would permit a pitch clock, shift ban and enlarged bases in 2023." - @ Bob Nightengale
The shift ban is highly controversial and will mean that teams can no longer overload their infields to one side or another and instead will have to play their traditional positions. This will likely lead to an increase in offensive production and a more traditional style of baseball. The pitch clock is not as controversial as the shift ban and will greatly improve the pace of play. It should also keep fans engaged throughout the game.
The last rule change worth noting for 2023 is enlarging the bases. This may entice players to attempt more base steals, as the runners would now be closer to each base than before.
The use of the microphone is long overdue and should have been implemented with instant replays in 2008, later expanded in 2014. Look for this new change to help fans across the board better understand the game of baseball.