Hopefully NuNu Cromunda. Current edition launch was 2017 and they have wrapped up all gangs with expansion and gangs specific books ala codex style.
They did say in the roadmap there's a new gang coming by the end of the year.
I hope you're not advocating for a new edition... I mean, you're entitled to your opinion and all, but edition churn is the root of all GW
evil, not just 40k
. I'd rather see them actually break new ground... Rather than hit a reset button and rerelease the same stuff they've already released twice.