There have been a few big ones that became public against western targets, e.g.:
https://www.google.com/amp/s/www.nytimes.com/2020/09/16/us/p...
https://gizmodo.com/report-chinese-hack-of-federal-employmen...
But many of the rest have been concealed by the victims to protect business interests with China, which is why you haven't heard about them:
https://www.npr.org/2019/04/12/711779130/as-china-hacked-u-s...