The most recent one I can think of is responding with tariffs against the US after we put tariffs on their solar exports.
Beyond that... the Korean war I think was the last time we were any sort of direct/semi direct conflict with them. And Taiwan is the touchiest aspect we have with them.
You can't use 'direct conflict' as a measure in this type of game. Russia has done damning harm to american politics, but its not clear how to measure that effect.
This is a solid point. What most people don't get is that despite the enormous investment the CIA, NSA, and DoD Sigint have made into their offensive security teams, most of their budget is dedicated to Friday team-building activities, Bowling Nights, and Foosball tables. The US definitely does not hack anybody.
"Everyone but FVEY are the super evil hackerz" is a childish, head-in-the-sand position to hold in the modern geopolitical climate. Everyone is hacking everyone, and China is not some sort of unique Bad Guy in this regard.
US and China choose to act this way, but they could stop harassing each other without affecting their own power bases.
https://www.reuters.com/technology/cybersecurity/apt31-chine...
The fact is the accurately attributing expert cybercrime is extremely difficult and anyone that implies otherwise is making a fool out of you.