Passkeys, built on the FIDO2 standard, offer a significant advancement in authentication by replacing traditional passwords with a combination of trusted devices and biometric verification, effectively addressing security concerns and user experience challenges associated with PCI DSS 4.0 compliance. Unlike passwords, passkeys mitigate vulnerabilities such as phishing and credential stuffing, leveraging public-key cryptography to enhance security while ensuring a seamless user experience by enabling quick and effortless logins. These passkeys are synchronized across devices via cloud ecosystems, ensuring continuity and security even if a device is lost. Passkeys not only simplify compliance with PCI DSS requirements, including resistance to replay attacks, but also reduce operational costs by eliminating the need for password resets, thereby allowing IT resources to focus on more critical tasks. Their real-world applications include securing remote access, enhancing consumer authentication, and managing third-party vendor access, making them a robust solution for modern cybersecurity challenges.