Considered a proponent of closer ties with Beijing, Cheng is the first KMT leader to visit China in a decade, amid tensions over Taiwan's ruling Democratic Progressive Party (DPP), whose leadership Beijing doesn't recognize.
Beijing has framed Cheng's visit as a signal that there is political space in Taiwan for Chinese interests. Beijing considers Taiwan to be a breakaway Chinese province that should be "reunited" with the mainland. Xi has said that he prefers this be done diplomatically, but also frequently threatens the use of force.