SOX2 and glioblastoma: To investigate the potential impact of PD-1 blockade on the recurrent GBM tumor and immune microenvironment, we used Digital Spatial Profiling (GeoMx, NanoString Technologies, Seattle, WA, USA) to spatially select and profile the transcriptomes of tumor cells (SOX2+) and tumor-associated macrophages (IBA1+) in FFPE tissue samples from matched primary and recurrent tumors, with immunotherapy administered at recurrence in a subset of patients (Fig. 1a).