Last I have delved into the W40K the "time" was M40.999. This was at or around the 13th Black Crusade. Cadia is almost taken and most of the planets around the Eye of Terror have fallen to Chaos. Is there a continuity story or something from Games Workshop that tells us what "time" it is?
It is early M42
I previously assumed it was 999.M41, but with a bit more research, I've found that M42 has begun.
The Chronology of Events in the 40k universe has a section dedicated to M42. While no specific events have occurred, there is an account of what the general state of the universe is now...
As a new millennium dawns, the Imperium of Man faces dreadful threats on multiple fronts:
The Forces of Chaos, partially victorious during Abaddon the Despoiler's 13th Black Crusade in 999.M41, seize control of most of the surface of the world of Cadia in the Segmentum Obscurus, the gateway to a breakout into the rest of Imperial space. Only the Imperial forces' local naval and air superiority protects the Imperium from the greatest Chaos invasion seen since the Horus Heresy ten millenia before.
Hive Fleet Leviathan and the remaining splinter fleets from the earlier invasions of the Milky Way Galaxy by Hive Fleet Behemoth and Hive Fleet Kraken, continue to assault myriad worlds of the Imperium, slowly making their inexorable way towards Terra and the gleaming psychic beacon calling them like moths to a flame that is the Astronomicon.
The Tau Empire prepares for its Fourth Sphere Expansion in the Imperium's Eastern Fringes.
The Adeptus Mechanicus makes secret note that the technology of the Golden Throne of Earth continues to fail with no known way to repair the apparatus and keep the Emperor of Mankind alive.
The Necrons continue to awaken at a rapidly increasing pace on their Tomb Worlds across the galaxy, ready to rebuild their ancient interstellar empire, and wipe away all the "lesser races" that stand in their way.
1And it will never go forward, because Games Workshop doesn't want to bring those events to a decisive end. Sad.– YasskierSep 21, 2015 at 23:22
@Yasskier - Was looking over this question again this morning and realized, technically you are still right! There might be something on the horizon now with GWs changes, but despite moving the story forward they have still not really moved the story forward! haha– Odin1806May 26, 2018 at 16:02
Not a lot is known about what happens in 42M. From Ciaphas Cain Novels we can see that Inquisition is still in working order as Amberley Vail publishes the Cain Archive and that new books are still published because Amberley Vail uses them for extracts in the Cain Archive. You can try looking up 42M here.