Wikipedia claims: "On February 9, 2012, HTC announced in their Facebook page stating that Desire HDs would be upgraded to Android 4.0 Ice Cream Sandwich in late 2012."

Cyanogenmod does support your phone for CM7, but that's not ICS.

Somebody else has apparently dragged ICS from a different HTC device and shoehorned it into your phone (http://www.electricpig.co.uk/2012/05/16/htc-desire-hd-ice-cream-sandwich-update-how-to-get-it-now/). If you're going to go that route, make sure you do the backup routine after rooting your phone. Maybe it works, maybe it doesn't.

Or, you could just wait until "July-August" when HTC claims they will officially support ICS on your phone (link).