PDCD1 and neoplasm: Hurkmans et al. [37] investigated the tumor mutational load (TML), CD8+ T-cells, expression of PD-L1 and HLA class I. High TML, high CD8+ T-cells and no loss of HLA class I as well as high PD-L1 expression were associated with a better PFS and suggested that these were better predictive biomarkers for a response to anti-PD-1 immunotherapy.