These rules can be found on the GW web page. Some IG highlights.
From the PDF:
Forces of the Inquisition
• Codex Daemonhunters
• Codex Witchhunters
• Inquisitorial armies may take Imperial Guard and
Space Marine allies, chosen from the latest versions of
their codices. As both of these codices have changed
recently, use the following amendments to the list on
pg 30-31 of the Daemon Hunters book and page 26
of the Witch Hunters book:
Space Marine Tactical Squad, Space Marine Scout
Squad, Imperial Guad Infantry Platoon, Imperial
Guard Veteran Squad. Unit upgrade characters
may NOT be taken (i.e. Commander Chenkov,
Space Marine Assault Squad, Land Speeder
Squadron, Space Marine Bike Squadron, Scout
Sentinel Squadron, Armored Sentinel Squadron,
Rough Rider Squad, Scout Bike Squad
Space Marine Devastator Squad, Space Marine
Land Raider (Crusader and Redeemer as well),
Space Marine Dreadnought, Space Marine
Predator, 0-1 Leman Russ Squadron (Pask may NOT
Grey Knight Terminators may not travel in Valkyries
or Vendetta Gunships.
After the mess of the last years Ard boyz that let to the firing of the head community guy I won't be attending, good luck to everyone who does though.
Edited for linkage.