Its only been about a couple weeks since the last Banned and Restricted announcement (see "Wizards of the Coast Bans Cards from New 'Magic: The Gathering' Set Three Days After Official Release!"), and WotC is already banning more cards and altering mechanics. The latest cards to make the Banned list in the Standard format are Agent of Treachery (Core Set 2020) and Fires of Invention (Throne of Eldraine). In addition to banning these two cards, WotC designers also issued errata for the new Companion mechanic from Ikoria: Lair of the Behemoths.
The Companion mechanic now reads:
"Once per game, any time you could cast a sorcery (during your main phase when the stack is empty), you can pay 3 generic mana to put your companion from your sideboard into your hand. This is a special action, not an activated ability."
Wizards of the Coast also announced major changes to competitive level Magic: The Gathering events last week (see "Wizards of the Coast Announces Major Changes to Competitive Level 'Magic: The Gathering' Events").