LAMP3 (lysosome-associated membrane protein 3) is a dendritic cell-enriched marker with important roles in immune regulation and organellar homeostasis. LAMP3 localizes to lysosomal and late endosomal membranes 1 and regulates autophagy through inhibition pathways 1. Functionally, LAMP3+ dendritic cells represent a mature, migratory dendritic cell subset capable of trafficking from tumors to lymph nodes 2. These cells express diverse immune-regulatory ligands and modulate multiple lymphocyte subtypes 2. In cancer microenvironments, LAMP3+ dendritic cells play complex immunoregulatory roles: they mediate NK cell dysfunction and associate with poor prognosis 3, exhibit tolerogenic properties fostering immune suppression 4, and display reduced T cell priming capacity in metastatic lymph nodes compared to primary tumors 5. Beyond cancer, LAMP3+ dendritic cells expand in inflammatory skin conditions including atopic dermatitis 6 and psoriasis 7, where they interact with inflammatory fibroblasts through CCL19-CCR7 signaling to amplify type 2 and IL-17A responses. These findings identify LAMP3+ dendritic cells as key orchestrators of both anti-tumor immunity and pathogenic inflammation, suggesting therapeutic potential as immunotherapy targets.