TPM (Trusted Platform Module) is a standard cryptoprocessor used to store cryptographic keys
Trusted Platform Module (TPM, also known as ISO/IEC 11889) is an international standard for a secure cryptoprocessor, a dedicated microcontroller designed to secure hardware through integrated cryptographic keys. The term can also refer to a chip conforming to the standard.
One of Windows 11's system requirements is TPM 2.0. Microsoft has stated that this is to help increase security against firmware attacks.