CD8A and neoplasm: Although the transferred pmel-1 CD8+ T cells proliferated in the TDLNs of B16-F10-bearing mice, they were not found in either rat IgG- or anti-4-1BB-pretreated mice, which was likely due to their poor proliferation rate, while endogenous Thy1.1−CD8+ TILs were more abundantly found in tumor tissues of anti-4-1BB-treated mice compared to those of rat IgG-treated mice (Fig. 5b).