"You all seem very fit; that's great!"
Translation:Vous semblez tous très en forme, c'est génial !
I don't think it does. Even in English 'you' in its plural sense doesn't imply that as is clear in phrases like '2 out of 3 of you' or 'a few of you'. One needs to include 'tous' to translate the implied meaning of the English that every one in the group, without exception, looks very fit.
It must be some bad quality dictionary. Vous means "you" (plural or formal singular). Apparently they decided that instead of clarifying in parentheses, as I did, they would add the word "all" that is misleading because it narrows down the meaning and, furthermore, it gives the impression that vous tous is pleonastic.