IDO1 and diffuse large B-cell lymphoma: To identify immune‐modulating genes that correlate with the prognosis of patients with DLBCL, we conducted a prognosis analysis that stratified the expression of 43 genes reported as immune checkpoint molecules or their ligands including, ADORA2A, B2M, BTLA, CD24, CD27, CD28, CD40, CD40LG, CD47, CD70, CD80, CD86, CD247, CD274, CD276, CIITA, CTLA4, CYBB, HAVCR2, ICOS, ICOSLG, IDO1, IL2RB, KIR3DL3, LAG3, LGALS9, NCR3, PDCD1, PDCD1LG2, PVR, PVRL2, SIGLEC10, SIGLEC7, SIRPA, TIGIT, TNFRSF18, TNFRSF4, TNFRSF9, TNFSF14, TNFSF18, TNFSF4, TNFSF9, and VTCN1.