Tangem is a card-shaped wallet the size of a bank card, while Ledger sells USB and Bluetooth devices with screens and buttons. The design difference drives most of the trade-offs between them.
Tangem uses a backup system where you can create additional cards as backups, with an optional seed phrase mode. Ledger is built around a 24-word recovery phrase that you write down. If you like the classic seed-phrase backup, Ledger's model is more familiar.
Ledger's secure element and physical confirmation buttons are battle-tested. Tangem's card also uses a secure element and is tap-to-sign, which is convenient but gives less on-screen verification than a device with a display.
Tangem is extremely simple: tap the card to your phone and confirm. Ledger requires a cable or Bluetooth and on-device confirmation. Tangem wins on convenience, Ledger on control and transparency.
Choose Tangem if you want maximum portability and simplicity. Choose Ledger if you want a screen, physical buttons and the reassurance of a widely audited platform.