(a) Summarized schematic of the identification of organ-specific mesenchyme at an early stage of development and the signaling pathways involved for the differentiation by Han et al. [27]. Examples of epithelial-mesenchymal interactions involved in early organogenesis, where (b) the splanchnic mesenchyme induces medial constriction of the foregut to initiate the diversification of the Sox2+ esophageal and Nkx2-1+ tracheal epithelium and (c) the hepatoblasts invaginate and delaminate into the septum transversum mesenchyme for accelerated proliferation. Abbreviations, Single cell RNA sequencing (scRNA-seq), embryonic day (E), Lateral plate mesoderm (LPM), Foregut (FG), Bone morphogenetic protein (B), Fibroblast growth factor (F), Hedgehog (H), Notch (N), Retinoic acid (R), Wnt (W), Septum transversum mesenchyme (STM).