Here's my preditction for the future releases: (Dates are preorder dates)
20.6 -- Lumineth Army set
27.6 -- PA9 Pariah as that should be coming before 9th edition and it would fit into a 2 week cycle with PA7 and PA8
04.7 -- Rest of the Lumineth (normally as seen with the Sisters Army Set I would expect a longer delay but because of Corona it will probably drop here to make way for other stuff, same reason I don't expect them to be split into 2 weeks)
11.7 -- start of a 2 week preoder for 9th Edition 40k (this date and the 2 week preorder for release on the 25 has been rumoured in the last weeks)
18.7 -- either nothing to push 9th edition or some specialist game release (Necromunda, Underworlds, Warcry and AT all have stuff coming)
25.7 -- release of 9th so probably also smaller preorders to not distract from their main attraction
01.8 -- could see Sons here for release on the 8th but maybe a week later
Also stuff we know is coming but I have no idea when:
Specialist games:
Scions of Flame, DoK and Ironjawz Warbands, 3 Necromunda expansions, AT Defence of Ryza expansion, last Blackstone Fortress expansion with maybe a switch back to AOS Warhammer Quest after that?
40k:
Forgeworld Indexes, more Primaris and Necron releases (I think there was a shipping manifest for something new fo Custodes back in January?)
AOS:
Nothing confirmed to be coming expect the Aetherwar heroes to be released standalone but knowing GW that will probably only happen at the end of the year