You are not going to find much because China is not yet part officially of Horizons (South Korea and Japan are but not China).

Most of these collaborations happens under the hood and are peer-to-peer and project based.

I can speak for the fields that I am close to:

- For Astrophysics, China already provide both hardware and computing resources to some projects. Conferences in China are in common and exchange are frequents. Rumors of collaborations on Space and scientific satellites are also on the way.

- For nuclear physics, China is actively participating in several software stack used for nuclear fusion. There is also mutual collaborations on some nuclear fusion reactors and they regularly host conferences where EU researchers are invited. They progressed tremendously compared to 10y ago.

- For particle physics, China was historically playing alone and was planning to create and operate their own particle collider similar to the LHC in size. This is not on the table anymore. There is a deeper collaborations with several EU institutes including CERN, they also voiced their interest in the FCC project.

- For Neurosciences, their labs has permissions to execute wet experiments on animals that are forbidden on most EU territories and that I will not describe. A lot of data are shared both way between China and several EU labs. Many neurosciences related conferences have emerged in China, exchanges are much more common that they were.

- For HPC and A.I, this is by far the most active and pushed research domain actually. Alibaba, Tencent and others are even proposing computing resources for free on some projects in exchange of conference attendance in China and collaborations. There is not much collaboration on hardware (due to embargos and NDAs) but a lot of collaborations on software.