Gianluigi Donnarumma, who was the Euro 2020 Player of the Tournament, signs a five-year contract with French giants on a free transfer.
Sancho, who missed a penalty in the shootout, said as a society we need to do better and hold these "people accountable".
Italy ended 53 years of pain and prolonged England's wait for a global trophy as they won the Euro 2020 competition.
Italy survived a hard-fought Euro 2020 semifinal against a resilient Spanish side to win the contest in a penalty shootout.
Spain was by far the better team in the contest but it was just not to be for Luis Enrique's men as Morata failed to convert his penalty.
Italy have established a new record for the longest winning sequence in the UEFA European Championship, qualifying included.
The Italians withstood a late onslaught from top-ranked Belgium side to enter the semifinals of Euro 2020 to play Spain.
The upcoming Euros can become a stage of redemption for the Azzurri after years of lingering in the shadows ever since 2006.
Gianluigi Donnarumma will leave AC Milan next month as his contract expires on June 30, the 22-year-old goalkeeper made 251 appearances for the Italian giants.