CD8A and metastatic melanoma: It has been reported that CD8+CD103+ TRMs are critical for protection against melanoma in mice,11 12 and associated with improved survival in metastatic melanoma,33 although this may not be the case in primary cutaneous melanoma because TCGA data demonstrate reduced survival in primary cutaneous melanomas with high expression of ITGAE, which encodes for CD103 (figure 6H).