The 2038 FIFA World Cup is a planned association football tournament, whose host country or countries has yet to be decided. The next World Cup hosts will be as follows:
2026: USA, Mexico, Canada
2030: Portugal, Spain, Morocco (+ 1 game each in Uruguay, Argentina, Paraguay)
2034: Saudi Arabia
FIFA currently use a rule where a confederation (broadly speaking a continent, though there are some exceptions, e.g. Australia compete in the Asian confederation AFC rather than Oceania's confederation OFC) cannot host a World Cup if they have hosted either of the past two tournaments. By those rules, the 2038 World Cup will be limited to either CONCACAF (North America) or OFC (Oceania), though this would likely mean repeating some or all of the 2026 hosts, as the remaining countries lack the infrastructure to host such a big tournament. Of course, FIFA could change the rules to allow a different host or hosts.
This market will be based on which countries, confederation, regions etc. actually host at least one game of the 2038 World Cup (being awarded the tournament is not sufficient, as a country may end up pulling out of hosting, which happened with Colombia for the 1986 World Cup). If the tournament is delayed but still referred to as the 2038 World Cup (like UEFA Euro 2020), then that will count. If the tournament is cancelled completely, this market will resolve N/A.