IDO1 and neoplasm: An immunotherapy signature of 166 immune genes, including IFNγ-inducible genes such as IDO1, JAK/STAT, and HLAs, as well as checkpoint genes such as LAG3, CTLA-4, ICOS and PD-L1, was increased in patients with T-cell inflamed tumours, as opposed to desert tumours, suggesting that performing a gene expression profiling and PD-L1 correlation screen before patient’s entry to ICT could predict the patient’s likelihood to respond to ICT in clinical trials [74].