There are so many names on the line for the Rugby Championship, the Rugby Players Association says it is not enough to just be one.
So how should the world be viewing the tournament?
Here are five key questions to ask before the tournament kicks off on Thursday, with the BBC’s sports editor Robert Peston.
Will Australia win?
The All Blacks are unbeaten in 20 matches, beating Wales by 31-7 in Cardiff on Saturday.
But if they lose the Test series against Argentina on Friday, they will be left with a four-point lead in the world rankings.
In the Rugby Rankings, the All Blacks were ranked ninth, the Crusaders were ranked seventh, and New Zealand were ranked fifth.
So the All Black win, even if they don’t get the win against Argentina, would be a significant boost to their hopes of reaching the World Cup for the first time in 26 years.
They were in the top ten at the start of the year, but were beaten by Italy in the quarter-finals and then beaten by Wales in the final.
That was a crushing defeat.
Australia, who have lost just one of their last eight games, would also need a massive victory in the other Test series to secure the title.
Australia’s Test series schedule will be announced in the coming days.
The Rugby World Series takes place from March 29 to April 4.
How many teams will be involved?
The Rugby Champions Cup is a two-week tournament that has become synonymous with the Rugby League World Cup in the past.
The tournament is played in England, Wales and Scotland.
There are also three qualifying rounds for each tournament.
Australia will be the first team to qualify in 2019, with France, France-Barbados and Argentina joining them in 2020.
In 2020, England, France and France-Portugal will join the competition.
Australia have already qualified for the tournament, winning the 2017 tournament in Wales, and are the defending champions.
There have been only two Rugby Champions Cups held in England since it joined the competition in 2000.
Who will win the tournament at home?
Australia will take on Argentina in Cardiff.
They will have their best-ever home record, but have been beaten in every game at home this season.
The hosts have a record of 4-0, but this is the first of two meetings between the sides.
The teams have played each other in Cardiff, but the hosts are currently favourites.
In 2015, the hosts beat the visitors 27-23.
The only other time they have beaten Argentina in the tournament was in 2013, when the sides played in Cardiff and lost by 10 points.
The All Black team has never beaten Argentina on home soil.
Will there be an All Blacks World Cup squad?
There will be no All Blacks team at the Rugby Champions Trophy in Cardiff this year, as the World Rugby will hold a meeting on Thursday with the All New Zealand squad to decide on a replacement.
The squad will be chosen by a panel of members from the Rugby Football Union, and is expected to be announced at the same time as the squad announcement.
Who is the best Test team?
Australia is expected by some to win the 2019 World Cup, and there are several contenders.
France and Wales are both favourites to win their respective games, and both are undefeated in the Rugby Rugby League Championship so far.
The French side are unbeaten at home, winning all three games so far this season, while Wales have won the last three, including the Test against Argentina.
France is favourites for the 2019 Rugby World Championship, but they have not won a major international tournament.
There is no certainty that Australia will have to play in Cardiff against either the All Stars or the Wallabies, with both sides unbeaten this season and in the same position they were in last year.
What will be Argentina’s response to their loss to the All Whites in Cardiff?
Argentina have been in the World Tour for seven years, having won the 2014 World Cup.
The Wallabies are currently third in the rankings, with six wins from eight games.
The Argentines have not lost a game since they beat New Zealand in Cardiff in September 2015.
Argentina’s players will be under huge pressure to perform in the best possible way against the All Red’s, especially if they have to travel to the Pacific to face England.
Argentina will also be playing against a team that won their first ever World Cup final against Italy in 2013.
Who are the other teams that will be competing for the World Series?
Argentina, England and France will be all playing in Cardiff to decide their spots in the 2019 tournament.
The two teams have already played each others in the last two World Cups, with Argentina winning the 2014 Rugby World Championships and England winning the 2011 Rugby World Cups.
England won the 2013 tournament in England but lost to Australia in the next two rounds.
Who has won the World Championship in the previous 12 years?
The only previous winner of the World Tournament was Argentina in 2006,