PDCD1 and neoplasm: FlowSOM output also focused our attention on two metaclusters (M2, M5) that mapped to distinct viSNE coordinates in the tumor-associated PBMC relative to the healthy donors or tumor samples (Fig. 4m, n) and represented classical (M2) or intermediate/non-classical (M5) monocytic cells (Supplementary Fig. 5b) which were marked by CEACAM1 and PD1 co-expression even in the treatment-naive samples (Fig. 4l, o).