IDH‐SG patients showed clonal‐ITH values significantly higher than those of the IDH‐NO subgroup in both our cohort (P < 0.001, Student's t test) and the ICC_TCGA cohort (p = 0.049) (Figure 4D), demonstrating that the IDH‐SG of ICC tumors is featured with a high degree of ITH. Here, IDH1 is linked to intrahepatic cholangiocarcinoma.