In an interview with Fandango, Kevin Feige was asked if the mid-credits scene of Spider-Man: Far From Home will be a major storyline going forward. To which Feige replied:

Kevin Feige even compared Peter’s identity reveal to that of Tony Stark’s at the end of Iron Man. Making Spider-Man‘s identity one of the focuses of the sequel certainly gets this writer all sorts of excited. After all, Peter Parker is still a teenager who has to go to school. So how would that play out? Apart from that, in the comics, Peter’s identity has always been a big deal and the few instances where his identity is revealed has always lead to someone he loves being in danger. And now people know Peter’s identity. People now think he’s a villain, Mysterio plays one last trick on him and succeeds… [so that] means everything’s different. Where it goes, we’ll see. But it’s exciting that it once again sets us up for a Peter Parker story that has never been done before on film.”

Kevin Feige Discusses Spider Man s Secret Identity and Spider Man  Far From Home Sequel - 42