The Bianconeri announced the news on Twitter:
Cancelo will slide into the hole left by Stephan Lichtsteiner, who left for Arsenal as a free agent earlier this summer.
The 24-year-old will likely get the bulk of the starts over Mattia De Sciglio, although manager Massimiliano Allegri is notorious for bringing new signings along slowly―even Douglas Costa and Federico Bernardeschi had to wait their turn last year.
The Portugal international was a standout for Inter last year, joining the Nerazzurri in the deal that sent Geoffrey Kondogbia to Valencia. Inter had an option to make the deal permanent, but financial issues prevented them from doing so, per Football Italia.
Losing the player was a blow for the Nerazzurri, but losing him to Juventus will hurt even more.
The deal likely ends any interest Juventus may have had in Manchester United defender Matteo Darmian, who had been linked with the Italians, per Tuttosport (h/t Sport Witness).