In this review, we explore what is known about dendritic cells and monocytes in PID, highlight the recently described dendritic cell deficiency syndromes related to GATA binding protein 2 (GATA2) and interferon regulatory factor 8 (IRF8) mutations, suggest a practical solution to dendritic cell analysis in clinical practice, and speculate how best to further our understanding of dendritic cells in PID and immunity in general. Here, GATA2 is linked to pelvic inflammatory disease.