observed that in responders with metastatic melanoma, peripheral CD8+ T cells exhibit a higher proportion of effector T (Teff) or memory T (Tmem) cells and larger TCR clones, both of which are associated with sustained treatment efficacy.[133] These findings suggest that T cell populations and TCR clonality in peripheral blood are closely linked to intratumoral immune infiltration and responsiveness to ICIs. Here, CD8A is linked to metastatic melanoma.