CD274 and neoplasm: Baseline tumor samples (FFPE) were stained with multiplex immunofluorescence (mIF) for PD-L1, PD-1, CD3, CD8, CD68, and pancytokeratin in a single panel, scanned with the Vectra 3.0TM multispectral microscope, and analyzed using inFormTM 2.3.1 software.