How do you get the Worlds 2015 SKT T1 Champion Icon?
It was a mission or event reward. Riot's description in the client reads: “This icon was granted to players who owned the 2015 SKT T1 icon when they won Worlds that October.”
Is the Worlds 2015 SKT T1 Champion Icon still available?
No. Riot tied the Worlds 2015 SKT T1 Champion Icon to 2015 (mission reward), and it does not normally bring back past event rewards or bundles.
