Mari moved to the Premier League side in January from Brazilian side Flamengo, who he helped win the Brazilian Serie A title and Copa Libertadores in 2019.
The Spanish center-back played only two Premier League games for the Gunners before he was ruled out for the rest of the season due to injury.
Soares on the other hand joined the North Londoners on a short-term loan deal from Southampton in January and made five league appearances for Mikel Arteta’s side.
“I am really happy that we will have these players in our squad for the future. They have been part of the long-term technical plan Mikel and I have developed. They bring the right balance to our squad,” Arsenal technical director Edu told the club’s website.
"With Pablo we're all disappointed he got injured at Manchester City. Since Mikel arrived here he was asking for a central defender who was left-footed.
"We were really pleased with Pablo - his behaviour, the way he is training, his mentality and his quality. Unfortunately, he has that injury but of course we are really happy to keep him for the future.
"Cedric is also going to be an important player. He has been unlucky with the injuries but he is close to being ready and gives us more strength in the right-back position.
Arsenal have been busy in the transfer market, having already signed Willian from Chelsea on a free transfer.
Lille defender Gabriel Malgalhaes is said to be on his way to the Emirates Stadium after the Londoners agreed to sign him for €30m.
