What assets do you have in the US and what are the risks?
It is hard to answer your question without details, but if you own property or rent it out in the US, or own a business there, you will want to have liability coverage. If you are planning to drive a car in the US, you'll probably need some liability coverage. Does your international work involve any potential for a lawsuit? Might someone choose to bring a suit in the US? If so, you should consider professional liability insurance.
I am a long term resident overseas, but still have considerable assets in the US and rent out my home there, so I keep the same levels of insurance that I would have if I lived in the US, including an umbrella policy.