GZMB and cancer: Our data indicate that the circulating levels of unconventional T cells, including MAIT and γδ T cells, are depleted during cancer and disease progression. However, in high metastatic burden disease, the circulating Vδ1 population shows higher transcription of immunomodulatory and cytotoxicity genes NKG7, GZMH, GZMB, LGALS1 (Galectin 1) and FGFBP2 indicating a potential functional role of circulating γδ T cells during high burden metastatic disease.