CD28 and melanoma: Based on results obtained on Ag-specific CD8+ T-cell clones, we then investigated the frequency and fitness of CD8+ PD1+CD28− and PD1+CD28+ T cells in the peripheral blood of 68 patients with cancer of different derivation (n = 48 NSCLC, Table S1), n = 10 melanoma, n = 10 pancreas ductal adenocarcinoma cancer (PDAC)) and in 25 healthy donors (HDs), by multi-color flow-cytometry analysis (as outlined in the gating strategy, Fig. S2) (Fig. 2A,B), defined by the expression of CD28 and/or PD1 within CD8+ T cells.