In 2007, he joined the Graduate School of Medical Science and Engineering, KAIST, as an assistant professor and served there for a period of six years up until 2013.

From 2013 to 2018, he was appointed associate professor at the Graduate School of Medical Science and Engineering, KAIST.

His research interests span the fields of medical immunology with a particular focus on T cell responses to viral infection and cancer and immunopathogenesis.

[7] This study demonstrated for that bystander T cells can be a cause of host injury in human viral infection.

[12] His theory about bystander T cell activation has been highlighted as an important pathological mechanism in human viral disease.

[17] Moreover, he showed that memory T cells elicited by COVID-19 mRNA vaccination substantially respond to the Omicron variant.