As far as I know, only Cristiano Ronaldo who have expressed that Euro 2024 might be his last dance but now that he's with Al Nassr, we're not sure what will be his plans in the future as Al Nassr expressed that they might extend Ronaldo's contract if he still wanted to play but I think it's already unlikely since he will be over 40 years old by the time his present contract ends. But for Messi, latest speculation is that he will be with the team in the upcoming World Cup because they are the defending champion and that will be likely his last dance.
But I am still not sure whether Cristiano Ronaldo and Lionel Messi will play the next World Cup or not? However I personally see no chance of Cristiano Ronaldo playing, but Lionel Messi as the reigning World Cup champion captain may have some chance of playing if he is able to perform exceptionally well at the clubs. In fact, for me, the World Cup would not be complete without living legends like Cristiano Ronaldo and Lionel Messi.
martinez is a coach who looks like CR7 plays for the Portuguese national team more than other strikers, so we won't know what he will do at the 2026 world cup, but if he plays CR7 there, then CR7 will be the oldest player at the 2026 world cup later
meanwhile for messi, in 2026, he is still not 40 years old, so it is very likely that he will play for the argentina national team even though he has said he will retire at the world cup if argentina succeeds in becoming champion