Recently the nuclear transcription factor TOX (thymocyte selection-associated HMG BOX) has been identified as a critical regulator of CD8+ T cell exhaustion. In CD8+ T cells, persistent tumour antigens activate calcium and NFAT signaling, inducing the expression of TOX in the nucleus which results in increased expression of immune checkpoint inhibitor proteins, decreased cytokine production and T cell exhaustion. High expression of TOX is also associated with resistance to anti-PD-1 immunotherapy, suggesting that combined anti-TOX and immune checkpoint inhibitor therapy may be a new approach for patients resistant to immunotherapy treatments. Although TOX has recently been identified as a critical regulator of T cells exhaustion little is known about the upstream signaling networks that regulate TOX activity. Using proximity ligation assays, we recently discovered that nuclear PKC-theta (nPKC-θ) forms an exhaustion complex with TOX and other exhaustion transcription factors (EOMES, ZEB1) in dysfunctional CD8+ T cells. Furthermore, we also show that the nuclear PKC-θ+/ZEB1+ signature was higher in CD8+ T cells isolated from metastatic melanoma patients resistant to immunotherapy compared to responders and that in vitro inhibition of nPKC-θ reduced the nuclear PKC-θ+/ZEB1+ signature in PD1+/CD8+ T cells in both immunotherapy responsive and resistant patients. Additionally, using peptide microarray screening we find that PKC-θ may directly phosphorylate ZEB1 to regulate its DNA binding activity and nuclear localization. Overall, we identify for the first time that PKC-θ is an upstream regulator of key exhaustion signaling networks in CD8+ T cells.