This bill increases funding for U.S.-Israel cooperation on detecting and destroying underground tunnels used by terrorist organizations. The legislation raises the authorized spending from $50 million to $80 million for anti-tunnel defense programs under a previously established 2016 defense law. According to the bill, terrorist groups like Hamas and Hezbollah have built extensive tunnel networks in Gaza and Lebanon for weapons storage, rocket launches, and military operations, and the United States faces similar threats on its borders and overseas. By enhancing joint research and technology sharing between the two countries, the bill aims to improve America's ability to address subterranean threats while supporting Israel's military capabilities. The legislation affects the Departments of Defense and Homeland Security, which work to develop and apply anti-tunnel technologies for U.S. security purposes.