This study investigates the spatio-temporal dynamics and functional roles of tumor-retained activated CCR7+ dendritic cells (DCs) in anti-tumor immune responses. Using a photo-tracking mouse model, the researchers found that while CCR7+ DCs are the dominant population migrating to draining lymph nodes (dLNs), a subset remains tumor-resident despite CCR7 expression. These tumor-retained CCR7+ DCs are phenotypically and transcriptionally distinct from their dLN counterparts and exhibit a "exhausted" state with prolonged tumor residence. They downregulate antigen presentation and pro-inflammatory transcripts, but co-localize with PD-1+CD8+ T cells in human and murine solid tumors. Following anti-PD-L1 treatment, tumor-retained CCR7+ DCs upregulate stimulatory molecules like XO40L, enhancing anti-tumor cytolytic activity. The study highlights the previously unappreciated heterogeneity of CCR7+ DCs and their role in supporting intratumoral cytotoxic T cells, which may influence the effectiveness of cancer immunotherapy.This study investigates the spatio-temporal dynamics and functional roles of tumor-retained activated CCR7+ dendritic cells (DCs) in anti-tumor immune responses. Using a photo-tracking mouse model, the researchers found that while CCR7+ DCs are the dominant population migrating to draining lymph nodes (dLNs), a subset remains tumor-resident despite CCR7 expression. These tumor-retained CCR7+ DCs are phenotypically and transcriptionally distinct from their dLN counterparts and exhibit a "exhausted" state with prolonged tumor residence. They downregulate antigen presentation and pro-inflammatory transcripts, but co-localize with PD-1+CD8+ T cells in human and murine solid tumors. Following anti-PD-L1 treatment, tumor-retained CCR7+ DCs upregulate stimulatory molecules like XO40L, enhancing anti-tumor cytolytic activity. The study highlights the previously unappreciated heterogeneity of CCR7+ DCs and their role in supporting intratumoral cytotoxic T cells, which may influence the effectiveness of cancer immunotherapy.