To date, multiple systematic reviews have conducted statistical analysis on the incidence of IH [2,18,19,20,26,27,28,29,30,31,32,33], and the results show that the combination of CTLA-4 inhibitors and PD-1/PD-L1 inhibitors has the highest incidence of IH. The gene discussed is CTLA4; the disease is isolated hemihyperplasia.