Former New York Red Bulls superstar Thierry Henry is the new head coach at Montreal Impact, while LA Galaxy great David Beckham is introducing expansion franchise Inter Miami.
However, Galaxy have lost the league's latest superstar after Zlatan Ibrahimovic, who scored 53 goals in two seasons, returned to Milan.
Both Los Angeles clubs are still plotting big seasons, and champions Seattle Sounders look well set for a title defence.
We pose five key questions heading into the new campaign.
Can Chicharito follow in Zlatan's footsteps?
The biggest departure of the offseason was followed by the most significant arrival. Javier Hernandez has long been linked with a move to MLS, and Galaxy secured the signing of the ex-Manchester United striker as Ibrahimovic's replacement.
Hernandez does not have the same global appeal as Ibrahimovic, but he may ultimately prove a better fit at Dignity Health Sports Park.
While Ibrahimovic competed for the MLS Golden Boot, Galaxy continued to fall well short of team titles, playing a direct style that suited their talisman but not the rest of their squad. Cristian Pavon and company should now thrive alongside Hernandez.
Are Supporters' Shield holders LAFC one-season wonders?
Galaxy did not need to look far for evidence of what could be achieved by a team all pulling in one direction, with Hernandez's Mexico team-mate Carlos Vela leading Los Angeles FC to a dominant record-breaking Supporters' Shield success.
Bob Bradley's LAFC were a joy to watch, but Shield winners have struggled in recent years to maintain standards - Toronto FC providing the most striking example as they slumped from first in 2017 to 19th a year later.
Defender Walker Zimmerman has departed, striker Adama Diomande is starting the season injured, and LAFC suddenly could have their work cut out in 2020.
Could Seattle finally provide a serious title defence?
It is not just the Shield that has proven tricky to retain. Not since Galaxy in 2011 and 2012 have a team won MLS Cup two years on the bounce.
Seattle have played Toronto in three of the past four finals, winning twice, and yet there is a decent argument Sounders have not been the best team in the league at any point over this stretch. That should be about to change - despite the disappointment of Thursday's CONCACAF Champions League exit.
The defence has been restructured over the past 12 months, with retired centre-back Chad Marshall a big miss, but there is real depth in midfield and attack. Joao Paulo is an exciting addition, while Jordan Morris is in the form of his career as Seattle aim to build on their second title.
Will Henry bounce back from his Monaco misery?
Henry turned Red Bulls into contenders in the twilight of his playing career, but his coaching exploits have not been quite so successful to date. The Arsenal legend lasted just 20 matches in his first senior role with Monaco, losing 11 times and conceding 36 goals.
There was still excitement in Montreal as Henry arrived at Impact, though, with the club in need of a boost. They have missed the playoffs in each of the past three seasons.
But this is no simple second job for Henry as he aims to prove Monaco was a disappointing one-off. Montreal have lost veteran captain Ignacio Piatti and are short in several areas.
Do Inter and Nashville look more like Atlanta or Cincinnati?
Beckham's Inter are not the only expansion franchise in 2020, as Nashville also make their debut. The league has swollen from 20 teams in 2016 to 26 today, and there are therefore plenty of examples to consider as they arrive in MLS.
The Miami outfit look to have taken heed of the ambitious Atlanta United, champions in their second season. For Tata Martino, Miguel Almiron and Josef Martinez, read Diego Alonso, Rodolfo Pizarro and Matias Pellegrini.
Nashville's spending has been more modest, trading within the league, but that does not necessarily mean they will follow miserable 2019 basement side FC Cincinnati. Nashville at least look solid.