The YubiKey Bio uses a three-chip architecture that stores the biometric fingerprint in a separate secure element, offering protection from physical attacks.
This, according to Yubico, allows the YubiKey Bio to “act as a single, trusted hardware-backed root of trust which allows the user to authenticate with the same key across multiple desktop devices, operating systems, and applications.”
For when biometrics are not supported, users can enter a PIN entered during the initial setup.
By having everything built into the key, it means that authentication mechanisms are protected from tampering even if the host systems are compromised.
The keys can be managed using the Yubico Authenticator for Desktop, an app that is available for Windows, macOS, and Linux. This is used to enroll new fingerprints and add or delete fingerprints when native platform and browser capabilities are limited.
Customers should choose the YubiKey Bio if they are:

Securing an account with a service that supports only FIDO U2F or FIDO2/WebAuthn protocolsAuthenticating using a desktop deviceIn cloud-first environmentsUsing shared workstations and are in mobile-restricted environments

However, there are situations where users will be better off using the YubiKey Series 5 keys:

They require broader form factors and NFC supportThe users need to work across desktop and mobile devicesUsers need to support applications and services using a range of protocols such as OTP, FIDO U2F and FIDO2/WebAuthn, and Smart card/PIVThey are securing legacy and modern environments offering a bridge to passwordless, utilizing non-FIDO protocols

The YubiKey Bio enables biometric login on desktop with all applications and services that support FIDO protocols, as well as offering out-of-the-box support for Citrix Workspace, Duo, GitHub, IBM Security Verify, Microsoft Azure Active Directory and Microsoft 365, Okta, and Ping Identity. The YubiKey Bio Series is available in USB-A and USB-C form factors, and keys are priced at $80 and $85, respectively. They are available for purchase from Yubico.