In the case of NENs, few studies have reported that the expression of PD-1 and PD-L1 is higher in grade 3 NETs and NECs than in lower grade tumors [55] and that TMB was low in grade 1–2 NETs compared to that in NECs [56], indicating that the different response to ICI treatment in WD and PD tumors may be partly attributable to the different expression of immune checkpoints and TMB. The gene discussed is CD274; the disease is Wilson disease.