In terms of evolution, likely the most important issue in the future of security is IoT and the connection of everything to the internet. Today it's about data theft and we have "my credit card just got charged fraudulently". The future is likely to be about control of the physical world, and events will be more like "every smart meter in California just self destructed and left every home in the state without power", "a dam just opened and wiped out thousands of homes", or "every self driving car on the road just intentionally crashed at the same time".
In terms of opportunities, one of the big problems in cyber security (or more likely a symptom of the actual problem) is a lack of cyber security professionals, with Cisco estimating a 1 million worldwide shortage. That's predicted to get exponentially worse as billions of IoT devices go online in the coming years. Anything that can address this lack of people power is going to be a huge opportunity, and logic states that more people is not and cannot be the solution.
Machine learning and AI that can predict, protect, and respond are probably the most obvious opportunities in cyber security, and there are already startups in this space.