Dendritic cells (DCs) are heterogeneous population of professional antigen presenting cells act as link between innate and adaptive immune system. Human DCs are generally classified as  conventional DCs (cDCs) consist of  two subtypes, cDC1 (CD141+Clec9a+CADM1+XCR1+CD11c+) and  cDC2 (CD1c+SIRPα+ FCERIA+CD11c++), plasmacytoid DCs (pDCs- CD123+CD45RA+CD303+CD304+),  inflammatory DCs or monocyte derived DC and  Langerhans cells (LCs). The ontogeny and different factors involved in the differentiation of human DC subsets are not well characterized. Here we show the critical role of notch signaling; a highly conserved juxtrakine signaling pathway in eukaryotes, for the generation of cDC1 and its effect on other DC subsets. cDC1s are a non-redundant subset critical for antitumor immunity. Their presence correlates with long-term clinical benefit and tumor clearance in animal models. Strategies such as mobilizing cDC1s into the tumor microenvironment, activating them with TLR adjuvants, or using cDC1-based cellular vaccines have demonstrated their capacity to drive antigen-specific CD8⁺ T cell expansion and tumor eradication. However, clinical translation of cDC1 vaccines is limited by their extremely low frequency in peripheral blood, restricting recovery of sufficient cells for multiple rounds of vaccination. Moreover, cancer patients often exhibit reduced cDC1 frequency and function, further constraining autologous applications. An alternative strategy is to establish robust in vitro culture systems that enable large-scale generation of functional cDC1s from hematopoietic stem cells (HSCs). Here, we present a cDC1 generation platform capable of producing bona fide human cDC1s at scale, providing a foundation for translational cellular vaccine development.