How exactly is Tangem Wallet a cold wallet? What is the working principle of the wallet?

A cold wallet is a vault for storing cryptocurrency that is not connected to the internet. On Tangem cards, the private key is generated when the wallet is created and the card is attached to the device using a hardware random number generator. It is then stored on the card, which is fully disconnected from the internet. The private key never leaves the card. The primary purpose of the wallet is to store the private keys securely. The app is simply a user interface allowing the cards to communicate directly with the blockchain.