POLD1 and colorectal carcinoma: analysed a data set of different solid tumors treated with immune checkpoint inhibitors: the frequencies of POLE and POLD1 mutations were 2.79% and 1.37%, respectively, with a high prevalence in CRC (circa 7%); in the overall population, 74% of the POLE/POLD1 mutated patients also had a pMMR/MSS phenotype.