The 2018 International Champions Cup kicks off on Friday, with Premier League champions Manchester City facing Borussia Dortmund at Chicago's Soldier Field in the opening fixture of the preseason tournament which takes place across three continents.
A World Cup summer has shifted the focus away from the club game, but with most major leagues now in the final stages of preparations for the new season, what questions do the big clubs need to answer during the ICC?
How will Real Madrid shape up in the post Ronaldo, Zidane era?
It has been a tumultuous summer at the Bernabeu and the ICC will give us a first glimpse of Real Madrid in the post-Cristiano Ronaldo and Zinedine Zidane era.
New manager Julen Lopetegui has had a month to prepare for the preseason after being sacked by Spain on the eve of the World Cup following Real's revelation that he agreed to succeed Zidane as coach of the Champions League winners.
But the former Porto coach will have to hit the ground running in games against Manchester United, Juventus and Roma, having taken his job in controversial circumstances and then being forced to accept the €100 million sale of Ronaldo to Juventus.
In many ways, it is an impossible job for Lopetegui. Zidane left his post in June after guiding Real to three successive Champions League titles and Lopetegui will be deemed a failure if he is unable to make it four in a row in the coming season. But he will have to do it without Ronaldo, the Champions League-winning machine whose 15 goal contribution last season was crucial to their third-straight title.
How will Lopetegui replace Ronaldo's goals? Will Gareth Bale be given a more regular starting role? Will Real push hard to sign either Neymar or Eden Hazard?
Some of Lopetegui's squad will miss the ICC tour or arrive late due to their World Cup efforts, but Real have big questions to answer, and they will need to give clues to some of them during their time in the United States.
What will life after Arsene Wenger be like at Arsenal?
Unai Emery has made a busy start at Arsenal since being announced as Wenger's replacement at the Emirates. The new-look Gunners will emerge in two ICC clashes against Atletico Madrid and Paris Saint-Germain in Singapore.
Per Mertesacker, Jack Wilshere and Santi Cazorla have been moved on by Emery, who has added top-level experience with the signings of Stephan Lichtsteiner, Bernd Leno, Sokratis Papastathopoulos, Lucas Torreira and Matteo Guendouzi.
Having finished outside the top four for a second successive campaign last season, Arsenal need to improve and Emery's first challenge is to get them back into the Champions League.
And the encounters with Atletico Madrid -- Arsenal's Europa League conquerors last term -- and PSG (who sacked Emery last season) will ensure that the new boss has high-quality opposition to test his team's early progress.
We can expect to see a harder-working Arsenal under Emery, with the likes of Lichtsteiner, Papastathopoulos and Torreira injecting some much-needed tenacity and winning mentality into the squad. But how will Mesut Ozil and Henrikh Mkhitaryan fit into Emery's Arsenal? Both are supremely talented individuals, but can Emery accommodate both in his team and, more to the point, will he want to?
If they fail to meet his demands for effort and commitment, they will not last long.
Is it Phil Foden's time at Manchester City?
Foden is in danger of becoming a superstar before he has barely kicked a ball at Manchester City.
The 18-year-old midfielder is regarded as one of the brightest young talents in Europe, with some billing him as the future of English football, but despite leading England's under-17 team to World Cup glory last year -- and being named as Player of the Tournament -- his opportunities at City under Pep Guardiola have been limited.
Foden, who first appeared in the ICC clash against Manchester United in Houston last summer, started just three first-team games last season, with his Premier League appearances restricted to five outings as a substitute.
With so many of Guardiola's star names absent from the trip to the U.S. following their World Cup performances, Foden is likely to figure highly in the games against Dortmund, Liverpool and Bayern Munich.
But whatever he does in those three games, will it be enough to convince Guardiola that Foden can make a difference in the Premier League and Champions League in the coming season?
The youngster, nicknamed the "Stockport Iniesta" by City fans, is now at an age where he needs to play regularly in order to develop as a player and test his ability against seasoned professionals. That may happen with a loan move away from City this season, but Foden has three games in the U.S. to persuade Guardiola that he is ready to make an impact.
Where are Man United heading under Jose Mourinho?
Mourinho isn't happy. The Manchester United manager has arrived in the United States with a squad depleted by the World Cup and he has described his preseason so far as "very bad." The only positive, according to the Portuguese, is that the "young boys have a fantastic opportunity to train with us."
Preseason campaigns can set the tone for the serious business that lies ahead, though, so Mourinho's mood does not bode well for United ahead of a crucial campaign at Old Trafford.
Having finished last season without a trophy and at second place in the Premier League, 19 points behind champions Manchester City, Mourinho knows that United must mount a genuine title challenge this season. But can they show the signs of recovery and progress during the ICC, in games against AC Milan, Liverpool and Real Madrid?
Mourinho has insisted that it will not matter if United lose those games heavily, due to the absence of so many of his top stars, but his squad is stronger than some, with Juan Mata, Ander Herrera, Anthony Martial and Antonio Valencia already in the U.S. and David De Gea, Nemanja Matic and new signing Fred due to arrive next week.
United need to show that the Mourinho plan is coming to fruition, regardless of the personnel involved, and the manager also has to give the impression that he believes his team are making progress.
What will we learn about Liverpool's ability to win the Premier League?
Liverpool will be blessed with a strong squad during their ICC campaign thanks to the World Cup being relatively kind to the club in terms of the workload of its players.
Virgil van Dijk and Georginio Wijnaldum had a summer off due to Netherlands failing to qualify for Russia, while long-awaited arrival Naby Keita also didn't make it with Guinea.
Sadio Mane and Mohamed Salah exited the World Cup at the group stage, so Jurgen Klopp will have the luxury of working with the majority of his players and it could be a big advantage for the Liverpool manager.
Although Liverpool made it to the Champions League final last season, it lost to Real Madrid in Kiev, and the priority at Anfield is to win the Premier League and end a long wait stretching back to 1990.
Klopp's summer signings of Keita, Fabinho and Xherdan Shaqiri, with Brazilian goalkeeper Alisson Becker an imminent arrival, have made Liverpool stronger and the ICC encounters with Dortmund, Manchester City and Manchester United will give them the opportunity strike an early psychological blow.
Liverpool have the appearance of a team that is going places, with a title challenge the very least to be expected this season. A positive performance or two in the U.S. will only add to the belief that this could be their year.