Slitherine

Is this going to be like a DLC? Will I be able to import a core form 1940?

No, this don't belong the GC DLC. So you won't be able to import your core.
This is an expansion with it's own 24 scenario campaign.

To be totally correct it is a stand-alone expansion.

Panzer Corps: Afrika Korps is an expansion for the existing Panzer Corps owners and a full stand-alone game for new players.

Thanks.