Machine Learning is a part or subset of Artificial Intelligence, as you might be knowing. But Operations Research is entirely very different from both technologies. It is the process of improving the operations of a physical company, team, or organization. What basically Operations Research does is that it relates all the factors that go into making operations smooth and considers them to make the equations of various variables, which when controlled, will produce the desired results.
Whereas AI is all about mimicking the human brain, its neuro connections, and the behaviors and decision-making abilities, to perform human-oriented tasks, efficiently without any form of human intervention. Machine Learning is a sub-domain of AI, that focuses on training a computer or machine from a specific set of datasets, that then trains the model to perform the tasks assigned to them efficiently and learn how to optimize them along the way.
The relation between them could be the subjects involved in it, Operations Research could be done only with statistics, on the other hand, AI, and Machine Learning both require Probability and Statistics. If you wish to master AI, or Machine Learning check out the Artificial Intelligence course and Machine Learning course from Intellipaat. Also, watch the following video on AI tutorial for beginners.