According to R.Hanson
As the West ponders whether Vladimir Putin will invade eastern Ukraine, Xi Jinping is watching. For Beijing, Ukraine is a convenient model for developing policy towards Taiwan. At the operational and tactical levels, the People's Liberation Army of China (PLA) will be able to gain invaluable information on how the NATO leadership will respond to the current challenges. As the Biden administration and NATO negotiate Ukraine's security with their Russian counterparts, the West should consider the message it intends to send to Moscow and Beijing.
Xi and Putin openly display a charismatic relationship and are proud to have met over thirty times since 2013, including a virtual summit in December 2021, apparently held in response to President Joe Biden's Summit for Democracy. During the videoconference, Xi said, "We firmly support each other in matters concerning each other's core interests and protecting the dignity of each country."
In 2018, the PLA dispatched about 3,000 troops to Russia's Eastern Military District to support the VOSTOK exercise. The PLA's lack of fresh combat experience is the Achilles' heel for its leadership. Thus, the CCP's sudden willingness to deploy thousands of troops outside its borders and subsequently allow a reciprocal number of foreign troops to enter its territory can be explained in part by an attempt to close this glaring gap.
As the Biden administration works with its European allies to develop a credible strategy for dealing with Russia, Ukraine should not be the only item on the agenda. The West must act on the premise that Putin's “best friend” will also be at the negotiating table. He may not have a voice in the discussion, but Xi's presence will be felt nonetheless.