Spider-Man: Far From Home had some pretty breathless revelations at the end there. Without getting too bogged down in what actually happens, the most important thing we need to talk about now is the secret Nick Fury has been carrying around for some time. Or, more accurately, the secret that Not Nick Fury had been carrying around.
Because Far From Home's second huge revelation confirmed what other theories had suggested for some time - that Skrull impostors had taken over the roles of humans on Earth without anyone noticing, just as they did in the Secret Invasion comics storyline.
The only major difference, of course, is that in the MCU, they were actually welcome. There wasn't any body-snatching and the Skrull were a benevolent race of refugees driven into hiding by the nefarious Kree who sought to wipe them out. After the revelation of their true backstory, they aligned with Captain Marvel and she helped travel the galaxy to find their scattered survivors to free them and help them fend off the Kree.
Judging by the history of the universe beyond that point as established in Guardians Of The Galaxy by Ronan The Accuser's mission of vengeance, the Kree end up being defeated and the Skrull simply disappeared. Presumably to a much-earned life of peace. Or so we might have imagined before Far From Home shook the foundations again.
The stinger on that movie revealed that the Nick Fury we'd seen interacting with Peter Parker and Mysterio all the way through was in fact a stand-in. In a delightful touch, the stand-in was in fact Talos the Skrull leader we'd met previously in Captain Marvel. The REAL Fury was off out in space, overseeing the development of a secret space station, by the look of it, with the help of the Skrull who had presumably been brought back together over the previous decades.
This was no mere gag for the sake of it: the space station means something. Nick Fury's involvement with the Skrull and the station MEANS something. The fact that there are Skrull on Earth means SOMETHING. And the fleeting mention of Kree sleeper cells in a throw-away comment by the Talos Fury in conversation with his wife, Not Maria Hill also means something. What we have to determine is not only what all of that means, but the other looming question that hangs over Fury's secret revelation.
Namely, when did Talos replace Nick Fury on Earth? Or at least, when did Fury use the Skrulls' abilities to pretend to be him in order to be somewhere else entirely?