Mackay is the Theme Leader in Immunology and Laboratory Head at the Peter Doherty Institute for Infection and Immunity.

[9] During this period, she was the first to describe the molecular program and developmental features that underpin immune cell tissue residence.

[10] Mackay established her research Laboratory at the Peter Doherty Institute for Infection and Immunity at the University of Melbourne in 2016.

[5][9] She has made significant contributions to the field of T cell memory and tissue immunity, with Mackay being listed as a Highly Cited Researcher™ annually since 2019.

In 2022, Mackay was the youngest ever Fellow elected to the Australian Academy of Health and Medical Sciences, with the citation on election describing her as “an internationally recognised expert in T cell immunity, contributing landmark papers that have defined how memory T cell responses are generated in body tissues”.