It depends on your specialization. Nevertheless, if you are looking for a "hot area" to work on within the core Data Mining/Machine Learning community, I would suggest going to the websites of top-rated conferences and look at their:

1- CFPs - call for papers - these are indicative of what the community is interested in right now.

2- Look at the accepted papers from previous years to get an idea of what is being worked on by various groups.

You can get a list of top-rated conferences at https://aminer.org/ranks/conf

Best of luck in your research

Computer Vision can be a new field and interesting to you.

Visit: CVPR and ICCV conferences and you will get some ideas there. Interestingly the papers are free. http://cvpr2019.thecvf.com/

http://iccv2019.thecvf.com/

Dear Is Kh Rasheed ,

It depends on your research interests. Anybody can apply AI or deep learning techniques in numerous research areas. However, if you are interested to contribute to exploring core machine learning techniques, that's a different issue. But you can use AI or ML in different state-of-the-art research areas like computer vision, information retrieval (IR), NLP, Healthcare, etc. In that case, you first need to grow your intention in any of the specific problem of the above-mentioned area. Then you can apply AI or ML techniques to contribute to that research area.

Hope my explanation will help (at least) to make your decision.

Here is a link for different research problem that contains different topics on IR and NLP.

https://sites.google.com/site/mdshajalalresume/resources

Is Kh Rasheed

It depends on your research interests. You can work in numerous fields such as Text mining, sentiment analysis, Recommender system, Robotics with ML, IoT with ML, ML in Blockchain, ML in E-learning/E-commerce, etc.

iot with machine learning

Machine Learning Algorithms:

Evolving Artificial Conception: Linking Picture and Sound with the Concept

Dear Friend, data mining is a set of tools which could be used in AI and Machine Learning as well. I believe that with your experience in DM a good area of PhD research would be Predictive Analytics. There are many interesting topics you can select for your research there...