15 December, the US will implement tariffs on $156B on China

To offset the additional tariffs the CNY would have to depreciate - although the Chinese authorities have said that they won't pursue quantitative easing.
If there is a formal announcement to suspend or delay the tariffs, the market would expect a more positive risk reaction and that is currently being priced in. WIth the USDCNY trading around the 6.90 and below the 7.00 psychological level that was key back in the summer.
If Phase one of the deal does not pass and the tariffs go-ahead, we would expect the USDCNY to trade above the 7.100