Can Artificial Inteligence threaten humanity?

We're already living in the early days of the post-Artificial Intelligence world. Experts say it will take 20 years before we will have human level Artificial Intelligence, but today examples exist were Artificial Intelligence beat humans i.e chess. Some experts are not worried but they are conscious of the fact the possible consequences have to be considered, and thus be better prepared for the future changements that Artificial Intelligence may bring.