Anything we, third party devs, write custom, for example TwitchPlaysPokemon takes input from chat.
Whats coming soon, no idea, they won’t tell us and they generally don’t comment on future plans.
The new interactive overlay stuff looks interesting but no docs and in closed testing right now. https://blog.twitch.tv/now-testing-new-interactive-features-for-twitch-streams-662dee8e61dc
In the end, the lowest common, all platform denominator is Twitch Chat, it works on all platforms, so you can accept input from there.
As always, if you are a game dev you might be better off talking to Dev Success more directly, but I’m not sure how best to reach them these days. Twitch Game Developer Playbook | Twitch Developers and https://devportal.twitch.tv/