Ask HN: best-paid field to speciaze in programming/IT?

I would rather do programming, but I don't mind if it's something related like pentesting, reverse engineering, etc. Bonus points if it's a field where programming in Python is at least an option, since I love it.

Is it Android development? iPhone development? Web development (probably not)? Machine learning? ...

What can I learn in the following year or months if I want a higher salary or, maybe, work as a highly paid contractor?