Xayah and Rakan were the first set of champions to be released with duo synergy and they might be the last we ever get.
According to one of Riot’s announcements, there are no plans to design champions with similar synergies in the foreseeable future.
Xayah and Rakan’s design was based off a concept of a couple where they would amplify each other’s abilities when near to each other. Although menacing on their own, when played together they make up one of the strongest bot lane duos in the current meta. Overall, the pair was a huge success on both cosmetic and gameplay premises when released in April.
Although it would be exciting to see similar champs in the future, many complications can arise. Having buffs unique to other paired champions can also lead to overcomplexity, and take away from the unique identity featured by Xayah and Rakan.
It might be disappointing that we would not be getting any more double champions but it might be for the best to keep that unique feel and overall health of the game.