Myeloid Cell Diversity: From Fundamental Biology to Disease States - ABSTRACT Support is requested for a Keystone Symposia conference entitled Myeloid Cells: Mechanisms, Diversity and Function, organized by Drs. Andrés Hidalgo, Daniela Quail and Lai Guan Ng. The conference will be held in Banff, Canada from January 28-31, 2024. Myeloid cells are major components of the innate immune system that are first responders to inflammatory cues and critical to engage long-lasting adaptive immune responses. Understanding the fundamental biology governing myeloid development and function in steady-state and inflammatory contexts is imperative to developing treatments to combat cancer, cardiovascular disease, neurodegeneration and other diseases. With the rising use of single cell technologies, the vast extent of myeloid diversity and heterogeneity is being unveiled for the first time, creating new knowledge gaps surrounding myeloid functional states in health and disease. This Keystone Symposia conference will explore transformative research concepts that challenge current views of myeloid biology. The conference program was designed to leverage cutting-edge imaging technologies to learn about myeloid innate immune functions across tissue environments. It will also promote discussions that will reevaluate the fundamental biology underlying myeloid development in steady-state and inflammation, as well as challenge current concepts of how we define myeloid cell subsets versus functional states. The program will also include sessions that will consider the impact of trained immunity or lifestyle on myeloid states in health and disease and discuss emerging concepts in metabolic regulation of myeloid cells in disease and aging. Attendees will learn about new tools and resources that are available to study the diversity of myeloid states in various experimental contexts and will be challenged to rethink existing dogma that underestimates the breadth of myeloid cell contributions to health and disease.