The highly rated defender joins for a £2.75 million fee from the Portuguese club.
The 18-year-old right back has signed a five year contract, which has an option for another year.
"I am very excited and it's a dream come true," said Cardoso after signing.
"I always dreamt of coming to England and now I'm here at this big, historic club, so I'm very happy.
"I'm an aggressive player, a little bit different on the pitch than off it.
"I'm calm, and I like to have the ball and build the game from the back. I'm here to work and to help the team reach their goals."