Whoa, this is a little early as we have not even gotten through the to Pre-Orders on the Ork Codex. However it is widely thought that we will be seeing a Genestealer Cult coming up soon, so this fits into that. Here is a look at the leak for Genestealer Cults
Please note that it is not known if these are real or not, so consider them rumors.
via Stepping Between Games