Not much is known about this & it's still a couple months away but I think it's safe to assume we'll see next years expansion announced here. With ShB having now concluded & 5.4 out in 10 days there should be only be two major MSQ patches left between that & 6.0 as well. I was still early into SB at this point in time pre-ShB so it's going to be quite exciting getting to experience the run up to a new expansion as it happens this time around
My release estimates:
5.5 - 6th April [Edit: Confirmed for 13th April]
5.56 - 22nd June
6.0 - 24th September
5.56 - 22nd June
6.0 - 24th September
Let's see how close I am lol.
6.0 may be called Forspoken.