Myeloid cells regulate tissue homeostasis, immunity, and inflammation, whereas their dysregulation contributes to cancer, metabolic, inflammatory diseases, and degenerative diseases. This Keystone Meeting will cover areas of long-standing interest as well as topical areas in the field of myeloid cell biology, including ontogeny and tissue specification, myeloid cell activation, immunometabolism, immunity and infection, mucosal immunity, and cancer immunology. Multiple myeloid cell populations will be discussed, including tissue resident macrophages, monocytes, dendritic cells, and neutrophils. The meeting will highlight the diverse approaches being used to study myeloid cell biology, including genomic analyses, single cell profiling, imaging, and metabolic profiling. Both basic and translational aspects of myeloid cell research will be covered. The goals of the meeting are to share recent advances in this rapidly evolving field, stimulate interactions between interdisciplinary groups of scientists, and define future areas of investigation in myeloid cell research.