Create a duplicate layer.
Convert mode to CMYK.
Look at channels and find the closet one that has the majority of the image silhouetted.Windows/Channels
Then duplicate channel.
Adjust levels and contrast as much as you can to isolate the subject. You may have to use the path tool and fill in any areas that may be missing.
Once you have the channel completely black, drag the channel down to the selection tool.
Inverse selection by one pixel and feather by one pixel. Invert the selection back and press “Delete” button.
That’s it! Now you can adjust the background 😀