In my perspective, If I were to be Argentina Lionel Messi, I will have retired with the record achievement he has so far in the last world cup competition which he lifted the cup, and with that trophy honor and reputation, he has done quite well. But nevertheless, things can go his direction and Argentina break record and the world cup back to back.
I also wanted the same thing for Lionel Messi. He has paid his good due to the country's progress in the last tournament. I also thought he was going to resign and hang his boot after the last outing which was for me a good way to retire from the international games while he also start planning on how he will transition from the position of a player to the position of the manager of clubs and the national team
I believe him also have thought it through and I believed his presence in this coming World Cup would rather be a motivation for the young once, they would need him to be their with them, to inspire them and share his experience on how tournaments like this are played.
Winning the last World Cup the whole world though Messi would retire on international games but since then he have always prove why he needs to be on the pitch, he bring in a lot of quality in that Argentina team and I still think it will be needed in the coming World Cup.
But I believe this would be his last dance in a World Cup tournament, he is a living legend and he has won it all internationally so let hope he enjoy his last dance.