Tomb of Annihilation — ruling 1

Dungeon cards are nontraditional Magic cards that begin outside the game. They are not part of a player's deck or sideboard.

Tomb of Annihilation — ruling 2

Dungeon cards may be put into a player's command zone using the venture into the dungeon keyword action found on some cards from the Adventures in the Forgotten Realms set. If any other effect tries to bring a dungeon card into the game, it fails to do so.

Tomb of Annihilation : règles, fonctionnement et interactions (MTG)

Tomb of Annihilation is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Trapped Entry — Each player loses 1 life. (Leads to: Veils of Fear, Oubliette) Veils of Fear — Each player loses 2 life unless they discard a card. (Leads to: Sandfall Cell) Sandfall Cell — Each player loses 2 life unless they sacrifice a creature, artifact, or land of their choice. (Leads to: Cradle of the Death God) Oubliette — Discard a card and sacrifice a creature, an artifact, and a land. (Leads to: Cradle of the Death God) Cradle of the Death God — Create The Atropal, a legendary 4/4 black God Horror creature token with deathtouch.

How it works : Tomb of Annihilation

Original English text — Wizards of the Coast / Scryfall

#1July 23, 2021· Wizards of the Coast
Dungeon cards are nontraditional Magic cards that begin outside the game. They are not part of a player's deck or sideboard.
No other card is named in this ruling.
#2July 23, 2021· Wizards of the Coast
Dungeon cards may be put into a player's command zone using the venture into the dungeon keyword action found on some cards from the Adventures in the Forgotten Realms set. If any other effect tries to bring a dungeon card into the game, it fails to do so.
No other card is named in this ruling.

Interactions with other cards

These cards' text mentions Tomb of Annihilation.

Acererak the Archlich

When Acererak enters, if you haven't completed Tomb of Annihilation, return Acererak to its owner's hand and venture into the dungeon. Whenever Acererak attacks, for each opponent, you create a 2/2 black Zombie creature token unless that player sacrifices a creature of their choice.