The primary cilium, a microtubule-based organelle, protrudes from the apical surface of mammalian cells. This organelle serves as a sensory ‘antenna’ for the cell and responds to environmental cues through complex signaling pathways. Among others, the Hedgehog signaling pathway heavily relies on the mammalian primary cilium and is necessary for embryonic development as well as tissue homeostasis. Dysregulations of the pathway have been linked to a variety of cancers, notably basal cell carcinoma and medulloblastoma. Genetic mutations leading to impaired functions of the primary cilium cause a number of diseases, termed ciliopathies. The importance of the primary cilium in developmental processes and its links to diseases propelled research to further understand the complex roles of the organelle.