“…Enhanced programmed cell death ligand 1 (PD-L1) expression in the tumor melanoma, non-small cell lung cancer (NSCLC), renal-cell carcinoma, prostate cancer, colorectal cancer [5][6][7][8] Presence of CD8+tumor-infiltrating lymphocytes melanoma, NSCLC, renal-cell carcinoma, colorectal cancer [5][6][7]9,10] High tumor mutational burden or neoantigen burden melanoma, NSCLC, colorectal cancer, urothelial carcinoma [5,11,12] Presence of intratumoral major histocompatibility complex (MHC) class II expression melanoma [5,13] Presence of intratumoral interferon-γ-immune gene signature melanoma, head and neck cancer [5,14] Low interleukin (IL)-6 expression in the tumor colorectal cancer [15] Peripheral blood count: low absolute neutrophils, low absolute monocytes, low myeloid-derived suppressor cells, high FoxP3+ regulatory T cells, high lymphocytes, high eosinophils, high CD19−HLA-DR+ myeloid cells, high CD14+CD16b−HLA-DRhi monocytes melanoma, NSCLC [5,[16][17][18] Low level of c-reactive protein (CRP) in the serum, low relative eosinophil count uveal melanoma [19] Serum proteome analysis: BDX008 melanoma [20] An alternative approach to the search of predictive biomarkers sensu stricto is the identification of predictive biomarkers which are determined under checkpoint inhibitor therapy but before evidence by radiologic imaging of response to therapy [18,21,22]. Table 2 provides an overview of treatment response monitoring biomarkers.…”