Usually, the response to ICB therapy depends on the following biomarkers: 1) the number of neoantigens derived from genome instability, such as the tumor mutation burden (TMB) and dMMR, and 2) tumor-infiltrating lymphocytes (TILs), mainly CD4+ T cells, CD8+ T cells and gene signals that interfere with the activity of T cells, such as those affecting PD-1/PD-L1/CTLA4 function 4,5. The gene discussed is CTLA4; the disease is neoplasm.