https://www.reuters.com/article/us-huawei-tech-usa-filing/huawei-challenges-u-s-defense-bill-as-sanctions-fight-ramps-up-idUSKCN1SZ08C >China's Huawei Technologies Co Ltd has filed a legal motion seeking to declare a U.S. defense law unconstitutional, in the telecom equipment maker's latest bid to fight sanctions from Washington that threaten to push it out of global markets.