DIE, FILTHY XENOS!
Dark Heresy deals only with the correct and proper race: humans. Not even those unfortunates born as abhumans (stunties, Ogryn and ratlings) are permitted, as only the best - humans, of course - may achieve so much in the Emperor's name. It deals with working directly for an Inquisitor, and such a role has no place for the foul abominations such as the ork, the
weeaboo tau and the eldar. They aren't even real people, after all!
At least, that's the tone the core rules goes by. Seriously, it doesn't present anything for abhumans or xenos, because of how rare it would be for an Inquisitor to make use of them (other than getting a truckload of them and dumping it on a battlefield, so that they can die in the place of guardsmen, allowing the guardsmen to die for the Emperor later on, against more important foes). CB might see things differently/allow a special case, though even then I imagine it'd help to have a copy of the rules.
But yeah, the DH book covers a specific kind of team. One of the later ones will apparently be more flexible, covering rogue traders and certain xenos.