What else do you know about Onecoin? Like any other cryptocurrency One coin too is a risky investment, but since it is not listed in coin market cap it doesn't necessarily be a reason to stay away, also the investigation because, do you think listing in coin market cap is the only means to prove that they are legit?
I have seen 100s of cryptos listed in coin market cap and has faded away after the initial excitements are over because they had no progressive plans on what to do with their stuffs where as One coin is taking time because I believe they have a very solid and futuristic plan to make their technology usable with the user base they have already created in the market. Hence I will not tell you invest in One coin, but I will warn you to not to jump in to conclusion with limited knowledge.