The answer to this question is not a simple one. Both AI and ML have their own strengths and weaknesses when it comes to data science.
AI is better at dealing with more unstructured data, while ML is better at working with structured data. AI also has the ability to learn on its own, whereas ML requires supervision.
However, both AI and ML are important tools for data scientists. The best approach is to use both together, in order to get the most accurate results possible.