Please note that I didn't use any commas in my sentence because the relative clause is a dependent one. Panel discussions titled Ask the Experts do involve Q&A or questions submitted by attendees.
By contrast, those titled Nachgefragt typically do not, IMO. Also, I didn't say anything about ask
ing, which could probably be used. I don't think that ask and asking are interchangeable in this context.
By the way, here's an ENS link using "inquire":
http://mpmgarts.com/inquire-experts-talk-arts-advocacy/It also points to Ramey's "experts talk XYZ." I half-agree with Michael here, though, because "experts" is a heavily overused word. Anyone can be one these days.
You should probably turn the phrase around, which means you'll end up with "Digital transformation: Panel discussion on/about the state of the HVAC market" or the like.
Best