Simplest answer most people give is big data, which is rather vague.Would it be healthcare, education or just e-commerce? I wonder if audit firms would be interested in using machine learning with blockchain technology. Or governments would want to use ML to trace bitcoin/blockchain transactions.
On top of what Jeronimo stated, finance (quants).
A good way to look at this is to look and where investors are putting their money in AI startups.
In a CBInsights report last year they highlighted 3 categories investors are focusing on are:
I run www.Welcome.Ai and constantly monitor the AI startups that are launching and coming into market.
Shoot me an email at firstname.lastname@example.org I would love to get your feedback and learn more about what machine learning work you are doing.