I'm not sure if Cao Yong, who was reborn in the late years of Kangxi, is Cao Yin's biological son because I lack relevant background information. Cao Yong, who was reborn in the late years of Kangxi, was a plot in a novel or TV series, while Cao Yin was an official of the Qing Dynasty. It was not directly related to whether Cao Yong had a biological son or not. If you have any other questions, I'll be happy to help you.