It purely depends on their ages.
Cristiano Ronaldo is 37 years and 9 months. By the upcoming February in 2023, he would already by 38. Considering that he would retire around the age of 40, the chances are most likely that he wouldn’t be able to take part in FIFA 2026 world cup.
The next FIFA world cup is to happen in 2026, to be jointly hosted by the three North American countries, Mexico, Canada and United States of America.
Lionel Messi is currently 35 years and 4 months old. By the next world cup, he would be 39 years old. So, it depends on when he would announce his retirement. There are some chances of him playing in 2026 world cup as well.
I would say, there are more than 50% chances of Messi playing in 2026 FIFA world cup. But the chances of Ronaldo playing the next FIFA world cup is very less. I would say, just about 15% or less.
PS : Just got to know that Lionel Messi has revealed in an interview with Star+ that he wouldn’t be playing FIFA world cup for Argentina beyond 2022. So, I presume, this would most probably be the last FIFA world cup for the two giants of the game.
Thank you.