With the patch note that they will change civilzation for some factions in Genish Khan campaign, I think they will release the update and DLC at the sametime.
But now, with all week nearly pass and they still promote for AOE 4, I think we might be wait to after Arpil 8th, after release of AOE 4. Especially as I see, many player feel uncomfortable with new DLCs with just 2 variant of AOE 4 so really really need to put that DLC up