He has 6 goals in 15 games, between League and CL. He has played 723 minutes in those competitions which is a goal for every 120.5 minutes he has played. He's scoring about once in every 6 shots for Dortmund. I think it's about 1 in 4 in CL, and 1 in 9 in Bundesliga. However, he has missed a large number of very good chances in that number, both in the league and in CL. That's the big complaint by Dortmund supporters and media, and is the reason he has been on the bench so much. No assists yet. 69% pass completion.
He is actually quite similar to Morata in terms of shot conversion, and goals per minute played. Morata has 4 goals in 14 appearances, but has only played 446 minutes in those matches due to featuring from the bench more often. That works out to a better goals per minute ration of 111.5 minutes per goal. He is slightly behind with shot conversion, at 1 goal for every about 7 shots. And like Immobile, he has a tendency to miss some real easy chances. No assists either. 77% pass completion.
The two have very similar statistics this year, with Morata slightly ahead in goals per minutes played, and Immobile slightly ahead in goals per shots taken. Morata has just turned 22, and Immobile is two months from 25. Morata has an advantage there, in that he is at a similar place to Immobile, while being almost 3 years younger, with both having switched leagues for basically the same price in the summer.