We further explored the correlation between YTHDC2 and eight immune checkpoint‐related genes and found that YTHDC2 was significantly associated with the expression of SIGLEC15, IDO1, CD274, HAVCR2, PDCD1, CTLA4, LAG3 or PDCD1LG2 in almost all types of cancers except for CESC and TGCT (Figure 5). The gene discussed is IDO1; the disease is cancer.