Predictive peripheral blood biomarker for checkpoint inhibitors

A method of treating a subject having cancer, comprising administering an antibody that specifically binds PD-1 (anti-PD-1 antibody) or PD-L1 (anti-PD-L1 antibody) to a subject identified as having (a) a circulating central memory T Cells (TCM):

• circulating T effector memory cells (Teff) ratio that is similar to or higher than the TCM:
• Teff ratio in the top 90% of healthy subjects;
• or
• both (i) a circulating CD4+ TCM:
• circulating CD4+ Teff ratio and (ii) a circulating CD8+ TCM:
• circulating CD8+ Teff ratio that are similar to or higher than those, respectively, in the top 90% of healthy subjects;
• wherein the anti-PD-1 antibody or anti-PD-L1 antibody is only administered to the subject if more than or equal to 1% of tumor cells in the subject express PD-L1 and wherein the Teff cells are negative for CD45RA and CCR7.