T cell immunoreceptor with Ig and ITIM domains (TIGIT) expression delineates an increase on tumor cells and antigen-presenting cells (APCs) isolated from the tumor microenvironment belonging to metastatic melanoma patients and this increase on CD8+ TILs isolated from metastatic tumor single-cell suspensions from seven patients with advanced melanoma stimulates metastasis through diminishing the proliferation of TILs [18]. Here, CD8A is linked to metastatic melanoma.