Moreover, we found that several immune checkpoint molecules exhibited close association with MTHFD2 expression, including PDCD1, CD274, CTLA4, CD276, CSF1R, IDO1, LAG3, HAVCR2, and TIGIT. In summary, MTHFD2 might be a new target of anti-tumor immunity, which contributes to the orchestration of immune cell infiltrates and the expression of immune checkpoint molecules. This evidence concerns the gene IDO1 and neoplasm.