We previously hypothesized that T cell responses to melanoma tumor antigens might be detected following ipi, even in the absence of therapeutic vaccination, and we reported evidence of type I (interferon-gamma producing), fully activated (CD69+) CD4+ and CD8+ antigen-specific T-cell immunity against NY-ESO-1 (cancer-testis), MART-1 and gp100 melanocytic lineage antigens following treatment with ipi at 6 weeks. This evidence concerns the gene CD69 and testicular cancer.