Disease recurrence following resection of the primary tumor was associated with lower proportions of OX40L-expressing myeloid cells, providing preliminary evidence for a potential link between myeloid OX40L expression and recurrence risk.<h4>Conclusions</h4>OX40L protein expression is a heterogeneous but prominent feature of the melanoma microenvironment, with cell type-specific expression patterns that include regulatory T cells. Here, TNFSF4 is linked to melanoma.