Maibach et al. (2020) described that the presence of lymphocytes in the melanoma tumour mass is usually an optimistic prognostic factor, but it depends on which population of T cells is detected, i.e., the presence of T lymphocytes (CD3+, CD8+, CD4+) and B lymphocytes (CD20+) correlates with a better prognosis for the patient, but Tregs (FOXP3+) are associated with a worse prognosis [30]. Here, FOXP3 is linked to melanoma.