Syngeneic tumor cell lines, MC38 (colon adenocarcinoma), MB49 (urothelial carcinoma), and LL/2 (lung carcinoma), that are highly, moderately, and not responsive to anti-PD-1 therapy, respectively (38), were injected into mice to develop three tumor models for investigating how metabolism is altered in response to anti-PD-1 therapy. The gene discussed is PDCD1; the disease is neoplasm.