IDO1 and neoplasm: The upregulated genes in PTCL‐TBX21 included Th1‐related genes, including CXCR3, CD38, INFG, CXCL9, CXCL11, IL27, and genes associated with tumor immunity, such as CD274 (PD‐L1), LAG3, and IDO1 (Figure 3B).