>>32731225NTA but some idol group actually collabs with male group on stage or making cameos on some content, World order (Genki Sudo) x AKB48 and their sister company collab is something that made me aware of idol culture years ago
https://www.youtube.com/watch?v=pDcNpSSoUr8Some kino Babymetal x Dragonforce if that counts, i'm not that deep into idols back in the day so i only know the surface but i'm sure professional collabs were a thing back then