PDCD1 and melanoma: In addition, CD4+ T cells with a TFH-like phenotype (CXCR5+/PD-1+/CXCL13+) colocalize with B lymphocytes in tertiary lymphoid structures (TLSs) that are particularly present within non-epithelial tumors, such as melanoma and sarcoma, and the presence of these TLSs correlates with better responses to immunotherapy and longer patients survival [140, 141].