Though they are not canonly together, there are many hints in official art work, the old and new anime that imply that they have strong feelings for one another. It is up to the audience on whether or not they want to interpret it as romantic or platonic love.
Ever since the beginning in the hunter exam, their hate for eachother turned into a strong bond. Kurapika easily rushes into mistakes and throughout slowly loses himself, but with Leorio's care, he is able to bring him back in times where its proven to be almost impossible.
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yeah they're canon
It's one of the best ships on hxh <3
They are just *chefs kiss*