CD28 and melanoma: Interestingly, mutations in the MAP2K2 gene have been implicated in the failure of immune checkpoint inhibitor treatment in melanomas.82–84 Markers of naive T cells CXCR4, CD5, and CD28 were downregulated in the proximity of IRF7-KO (LFCCXCR4: −0.25, QCXCR4: 0.01; LFCCD5: −0.27, QCD5: 0.003; LFCCD28: −0.3, QCD28: 0.03) but upregulated in the proximity of IRAK1-KO (LFCCXCR4: 0.06, QCXCR4: 0.6; LFCCD5: 0.26; QCD5: 0.04; LFCCD28: 0.31, QCD28: 0.06).