Doctor Who: 10 Dropped Plot Threads We'll Never Get The Answer To
3. Is Gallifrey Actually Back?
50th anniversary special 'The Day of the Doctor' changed history when the Doctor saved Gallifrey by transporting it into a different universe rather than destroy it, as previously established. The very next episode, 'The Time of the Doctor', then explained that the Time Lords were trying to return to our universe via the cracks in time.
In season 9's 'Hell Bent', however, it's revealed that the Time Lords wasn't actually moved into a different universe but could be found at the end of time. Though the Doctor had to get there "the long way round" via his confession dial, he was able to use a TARDIS to run away again. So it seems, unlike during the Time War, Gallifrey is no longer time-locked.
So does this mean that Gallfrey is returned and, just like the old days, the Time Lords are back for good? Well, that's hard to say as season 10 decided to ignore this question completely. And, going by Chibnall's description of season 11, it seems unlike that Thirteen will take a trip back home as it wouldn't be particularly casual viewer-friendly.
From the evidence, though, Gallifrey is back - but the Doctor is happy not visiting it. Very much like the old days.