Since Pokémon Legends: Arceus focuses on a single-player experience in the Hisui region, many features that players used in previous entries of the series have been removed. One of these features is trade evolutions, which a handful of Pokémon required in order to evolve into their more powerful forms.
Kadabra, the Psy Pokémon, is an example of the many Pokémon that received a new evolution method with the removal of trade evolutions. Throughout the Pokémon series, Kadabra has historically only been able to evolve into Alakazam, one of the most powerful Psychic-type Pokémon, through trading with another player. If the player that sent the Kadabra wanted their Alakazam back, they’d have to undo the exchange. Though trading returned in Legends: Arceus, this tedious method is no longer the way to evolve a Kadabra.
The new way to evolve Kadabra into Alakazam is through using the new Linking Cord item, which looks very similar to the Link Cable that players would use to connect their older generation Pokémon games. The Linking Cord can be obtained through trading Merit Points at the Trade Post in Jubilife Village, though it costs 1,000 MP to do so. It can also be found occasionally in space-time distortions, though is not guaranteed to appear in one.
Once players evolve their Kadabra into Alakazam, they will have one of the fastest and most powerful Psychic-type Pokémon in the series. While Alakazam suffers from its terrible defenses, its expanded move pool in Legends: Arceus makes it a great addition to any team.