Derby della Madonnina
Cancelo suffered a knee ligament injury in late August 2017 while on international duty, going on to be sidelined for one-and-a-half months. He returned to action during the 3–2 home victory over A.C. Milan in the Derby della Madonnina, featuring 20 minutes. After a few weeks of adaptation in the Serie A, Cancelo made his debut as a starter at the Coppa Italia in a home victory against Pordenone. On 17 April 2018, he scored his first league goal with a free kick in a 4-0 home victory over Cagliari.