Whereas treatment with anti-LAG-3 alone or anti-PD-1 alone delayed tumor growth in a minority of treated mice (0–40%), dual therapy with anti-LAG-3 and anti-PD-1 resulted in complete tumor regression in 70 and 80% of mice with fibrosarcoma and colorectal tumors, respectively. The gene discussed is PDCD1; the disease is fibrosarcoma.