My great-grandmother was a Kline, but the original spelling was Klein. Her ancestors came from Germany. Cline could very easily be a variation of Kline, or of some other surname, but with the DNA matches with Kline, I would lean that way.
So many surnames have had spelling changes through the generations, even sometimes among siblings. For ex., my maiden name was Runnells, and almost everyone heard it as Reynolds -- I was almost disgusted with having to correct spelling when to my ear there was a distinct difference in pronunciation! Then I discovered the immigrant ancestor was Reynolds! Though I have since found his name written as Runnells, and his descendants used several different spellings.