If the name of the card depicting the planeswalker in this trading card deck doesn't give away the deck's color, we don't know what will. Speaking of the planeswalker, this is Chandra, Flame's Catalyst, and as such, the deck's color is red.
Chandra is one of the 5 preconstructed planeswalker decks released for the M21 Magic: The Gathering expansion from 2020. M21 stands for Magic 2021. This game expansion has a theme of cats versus dogs, and the Chandra deck has only one card depicting a wolf-like creature.
Other cards in this deck are 22 Creatures, 11 Instants, and 1 Enchantment. All the decks in M21 have 25 lands, each. All the lands in this deck represent mountains.
Chandra, Flame's Catalyst Decklist: