Literal:
英雄 (yīngxióng, hero) +
联盟 (liánméng, league/alliance) — direct translation of 'League of Legends'. Players sometimes call it
撸啊撸 (lū-a-lū, 'LoL-LoL') as wordplay on LOL initials and the verb
撸 (mess around with). The mobile spinoff is
英雄联盟手游 (LoL Mobile/Wild Rift).