The marketing of this show killed it. It didn't pull people in to watch it. They wanted to be "Dr Jekyll and Mr Hyde" without coming out and saying it. People love that concept of the good vs evil all rolled into one person. But people want instant gratification and want to be told... this is what it is... and not play games. If the network wanted the audience they should have went after them and grabbed it.
The commercials for the show were too cat and mouse about the series plot. Look at "Hannibal", there is nothing ambiguous about the concept. "Elementary" is the catch-phrase for Sherlock Holmes. "Dexter" was good by day... serial killer by night... they were never ambiguous about it.
Those behind "Do No Harm" didn't have the stones to put it out there about the character. Those behind it didn't have the stones to go after what they needed. Those behind it, stabbed it in the back before it even made it to premier.