Trusted Execution Environments (TEEs) are secure areas within a device's main processor that execute code and process data in isolation, protecting sensitive information from both internal and external threats, even if the operating system is compromised. TEEs are established at the hardware level and run their own operating system, operating Trusted Applications that have access to the device's full performance while remaining isolated from untrusted applications. This technology enhances data confidentiality and integrity, making it crucial for environments handling sensitive data, such as edge computing and personal devices. TEEs also play a role in ensuring compliance with data protection regulations and are widely used in smartphones, IoT devices, and secure platforms like Apple's Secure Enclave and Google's Trusty TEE. Despite their benefits, including secure collaboration and simplified compliance, TEEs face challenges such as high implementation costs, vendor lock-in, and potential vulnerabilities in the TEE operating systems and Trusted Applications.