With the launch of the Ionian lore updates and Irelia’s rework, there is a new special mission to complete. Once you finish it, you earn an Ionia icon to rep your (potentially) favorite region of Runeterra.
The mission is as follows:
The Spirit of Ionia
Win a game with an Ionian champion on your team.
Reward: Ionia Faction Icon
According to the Universe page for Ionia, the Ionian champions are Irelia, Ahri, Jhin, Yasuo, Karma, Kennen, Kayn, Xayah, Rakan, Akali, Lee Sin, Master Yi, Shen, Soraka, Syndra, Varus, Zed, and Wukong. This means there are a whole ton of champions that you (or your teammates) can play as to get that icon!
As of writing this, the League client says there are 12 days of this mission left, which means you should have until around April 16 to complete the mission and score your icon. Good luck on the Rift!