I believe this when I see it happen since the ROK has literally vowed to take over operational control from the US military for decades to only keep putting it off:
He vowed to strengthen the Korea-U.S. alliance while beefing up domestic military capabilities in order for the country to command its own troops in the event of a conflict.
“My administration is pursuing the early takeover of wartime operational control,” he said. “The handover on the basis of our independent defense capabilities will ultimately lead to a remarkable advancement in the fundamentals and abilities of our military. When the South has wartime operation control, the North will fear us more, and the people will trust our armed forces more. With elevated self-esteem, our military will become stronger, and the Republic of Korea will emerge as a security hub in Northeast Asia. I am convinced that our military is equipped with such capabilities. The people and I have confidence in our armed forces.”
Recovery of wartime operational control of the Korean forces from the United States was a presidential pledge of Moon. During the Roh Moo-hyun administration, Seoul and Washington agreed that the transfer would take place in 2012, but the plan was delayed by the succeeding conservative presidents. Moon said he will complete it during his presidency, which ends in May 2022. [Joong Ang Ilbo]
You can read more at the link, but I think this may have a real chance of happening this time since President Trump reportedly wants the same thing. Anyway this whole OPCON issue has historically had little to do with military strategy and more to do with being a reactionary response to Korean nationalism. I had reach way back in the archives, but ROK Heads can read how President Moon’s mentor former President Roh pushed this same issue from this 2005 posting.