I would recommend machine learning as a very useful skill to acquire.
I have to be more specific because "machine learning", "artificial intelligence", and "data science" are really large topics that can encompass difficult math and PhD research.
For application programmers, I think a very realistic subset is using an existing "machine learning toolkit or API" (e.g. Keras in Python) to analyze data and solve problems. You use the machine learning algorithms but don't necessarily write them from scratch. This level of proficiency only requires high-school math. The analogy would be knowing SQL even though one doesn't write b-tree algorithms from scratch or using the "=PMT()" function in MS Excel without deriving the annuity equation from first principles.
I think machine learning concepts (classification, clustering, etc) will become an expected baseline of programmer knowledge just like SQL was 25 years ago. Its usage will become more pervasive and will be utilized by more people that don't have "data scientist" in their job title.