CD274 and neoplasm: A recent study identified four PC patterns based on PD-L1 expression on tumor cells (TC) and immune cells (IC): “adaptive-1” (TC: 0, IC > 1%), “adaptive-2” (TC > 1% to <25%, IC > 1%), “constitutive” (TC ≥ 25%, IC: 0), and “combined” (TC ≥ 25%, IC > 1%) [66].