Azpilicueta is a tenacious player, he is surely good for Barcelona. But it will be a bit difficult for Barcelona to sign him because of having not enough money. They only want to sign a player who has the free-transfer status. Barcelona also wants to give a cheap salary for their new players, Azpilicueta may disagree with this policy. The only reason that Azpilicueta may consider moving to Barcelona, is once he can get a guarantee to play regularly there. He has a strong competitor in Chelsea, Reece James. Azpilicueta may feel uncomfortable with the situation.
César Azpilicueta have been 32 years old and what your expectation if Barcelona get him on next season because I think 32 years old is not good enough contributing for team, have bad reputation with Barcelona were usually busy activities with young player when transfer window opening, but right now almost all Barcelona target on next season with old player from César Azpilicueta until with Robert Lewandowski, I think have gone with reputation Barcelona active find young player and make business later by selling to other club with higher values. Last window transfer almost player coming to Barcelona have old age just Ferran Torres as young player.