Professor Simion's work lies primarily in epistemology (epistemic justification, epistemic proper function, social epistemology, disinformation, evidence); ethics (wellbeing, trust, trustworthiness, moral psychology, ethics of AI), and philosophy of language (conceptual engineering, contextualism, speech act theory). Her work is also often interdisciplinary, with social psychology, social and political science, media studies, medicine, and computer science. She is the author of three monographs: Shifty Speach and Independent Thought (Oxford University Press 2021); Sharing Knowledge (Cambridge University Press 2021), and Resistance to Evidence (CUP 2023). She is PI of 'Knowledge Lab'- a major, 5-year research project funded by the European Research Council, PI of the 5-year 'Dimensions of Wellbeing' industry-funded project, and Co-I of a3-year Leverhulme Trust-funded project ('A Virtue Epistemology of Trust').She is also the winner of the Young Epistemologist Prize 2021.