From https://metaculus.com/questions/17282/tsmc-fab-shutdown-before-2025/

Taiwan Semiconductor Manufacturing Company Limited (TSMC; also called Taiwan Semiconductor) is the world's most valuable semiconductor company. NVIDIA, the main manufacturer of GPUs powering most top AI models such as OpenAI's GPT-4, spends billions on TSMC chips, and in March 2023, the NVIDIA CEO confirmed plans to use TSMC's new plant in Arizona.

TSMC is building this new chip fab in Arizona in part due to US subsidies, and presumably in part due to risk of their primary plants in Taiwan due China's posturing. (See this question for the probability of a full-scale invasion of Taiwan by China by various years.)

In addition to a full-scale invasion, China may attempt strategic attacks on TSMC, such as via cyberattacks or via social engineering, possibly as part of strategy against Taiwan more generally, or possibly as an attempt to slow down AI progress from consumers of NVIDIA GPUs based on TSMC chips, of which the US has banned exports to China as of Sept 2022.