The Immortal Sun is a mythic Legendary Artifact card from Commander Masters (CMM), collector number 393. Current market price: $11.99 (foil $15.03), TCGplayer market prices via Scryfall.
Players can't activate planeswalkers' loyalty abilities. At the beginning of your draw step, draw an additional card. Spells you cast cost {1} less to cast. Creatures you control get +1/+1.