Despite success of immune checkpoint blockade (ICB) for treatment of solid tumors, many patients fail to respond, with various systemic and tumor microenvironment (TME) factors influencing outcomes. A mature regulatory dendritic cell population (mregDCs) recently identified in non–small cell lung cancer (NSCLC) was shown to be one of these barriers to achieving anti-tumor immunity. While these cells exhibit a mature, migratory, and regulatory phenotype that has been partially defined in the TME, their differentiation cues, cellular interactions, and functional roles in lymph nodes (LNs) remain unclear. We hypothesize that TME-derived cues generate mregDCs, which transition to a regulatory state in tumor-draining LNs, limiting anti-tumor immunity. To investigate this, we constructed single-cell RNA-seq atlases of DCs from public datasets (NSCLC, head and neck cancer, melanoma) and sentinel LN biopsies from melanoma patients generated in-house. Across tissues, mregDCs share conserved transcriptional signatures enriched for non-canonical NF-κB signaling. However, mregDCs in the LNs exhibit increased inhibitory markers and reduced expression of stimulatory markers when compared to tumoral mregDCs. Importantly, when we integrate tumor and tdLN samples we see a differentiation trajectory linking tumoral mregDCs to a terminally differentiated LN-restricted mregDC population expressing the tolerance-associated transcription factor AIRE. This AIRE+ mregDC state has a distinct transcriptional profile highlighted by a regulatory phenotype and less of a maturation phenotype. When analyzing these LN mregDC populations, we see an increase in interactions with T cell subsets in invaded versus uninvaded LNs. In vitro experiments using to promote DC maturation and non-canonical NF-κB signaling are underway to define factors driving mregDC generation and progression to AIRE⁺ LN DCs. Overall, our findings identify a link between tumor-resident mregDCs and LN-resident DCs central to shaping anti-tumor immunity, highlighting LNs as a key therapeutic target and providing a rationale for LN-directed strategies to reduce immunosuppression and enhance ICB responses.