Messi will turn 33 midway through the group stage of the 2020 Copa.
Scaloni said: "I don't know if it will be the last. Hopefully not. But Argentina need the title, more than just him. Hopefully, don't promise anything, but we'll give the maximum to reach the final."
Unlike the 2019 edition, in which eight teams advanced to the quarter-finals from three groups of four, next year's competition will see the teams divided into two groups of six with the top four of each advancing.
Argentina, who will host the competition alongside Colombia, have been drawn against Australia, Bolivia, Uruguay, Chile and Paraguay:
Here's a look at La Albiceleste's schedule for the group stage:
Argentina will open their campaign against Chile. La Roja beat them on penalties in the 2015 and 2016 Copa America finals, though Scaloni's side did come out on top in the third-place play-off in this year's tournament.
Scaloni welcomed the challenge:
"It's a nice game to start. Anyone would have been difficult because the debut is always difficult, but this one has a special feeling.
"Chile has always been difficult for Argentina, especially in recent times. Difficult, but we are fine."
For all the talent they possess, Argentina have often underperformed in recent years.
Argentina football writer Roy Nemer was encouraged by what he saw from La Albiceleste when they beat Brazil 1-0 and held Uruguay to a 2-2 draw in November, though:
If they finish in the top two of Group A, they'll play on home soil up until the final, which will be played in Barranquilla, Colombia.
Colombia will be on home soil throughout if they do the same in Group B, where their biggest rivals will be defending champions Brazil, who did not even concede a goal in this year's competition until the final.
The Selecao will face off against Los Cafeteros on June 27 in their fourth group-stage match.
Asian champions Qatar will return as one of the two guest sides, while Australia will make their Copa America debut.