Call it Juventus, Milan, Napoli and Roma. It is certain that these four teams will be very tough competitors for Inter next season. Because of these four teams, you could say that the teams in Serie A are the most active in the transfer market this season. So it is clear that these four teams are very serious about preparing their teams for next season. Therefore, Inter really has to be aware of this.
To be honest, I haven't received any official news about the players they will recruit next season. Juventus and AC Milan are indeed tough competitors for Inter Milan for next season. I can say that this season Juventus and AC Milan cannot put pressure on Inter Milan who dominate Serie A. But if they are active in the transfer market this season I think they will really be a tough competitor for Inter Milan.
I don't know how AS Roma and Napoli will fare next season. As Roma will be better next season because I see De Rossi is a great coach. Napoli performed very badly this season. I'm not sure they will be contenders for the Serie A title next season.
So far no player has been officially announced to be signed by a the big teams because indeed many of the players they are currently targeting are still playing in the euro and also focusing on the Copa América, but indeed Milan, Inter, Juventus and several other teams have been actively moving to recruit the players they need to improve the quality of their team next season, I think for now the club is more inclined to postpone the inauguration of the agreement with the new player in order to keep the player focus with their national team, this season we see an incredible resilience from InterMilan in winning the Scudetto but it will be difficult for InterMilan to maintain the Scudetto next season if they do not improve the quality and quantity of their squad later.
I am quite sure that Serie A next season will be very tight, because currently many big teams are starting to improve their squads, both changing coaches and also targeting new players for them to get, many changes in the Serie A club club of course allow us to see many surprises that will occur next season, Roma and Napoli this season are not performing optimally in the scudetto competition, but if you look at the ambitions of Roma and Napoli this season which have having a new coach, of course we have the potential to see them get better next season, especially since Conte and Inzaghi reportedly have received support and also big funds from their management.