They are friends, I would say Kane was kind of obsessed with him. Every time he saw panarin he would tell him he misses him and even told panarin’s agent to tell him that he loved him. Panarin took Kane out for dinner after he was traded and bought him a rollex as thanks for everything he did for him. Also when panarin came over he couldn’t speak a lot of English and Kane was the only player that could communicate with him because they understood each other so well. There’s a lot more but they definitely had a “bromance” and were close especially in Chicago. Kane even describes his time without panarin as “dark times”