CD68 and neoplasm: For HPV ̄ tumours sub-stratifying by median CD68 cell density into high versus low groups showed a significantly higher level of PD-L1+ expression (P < 0.0001), (Figure 2C) and density of both CD8+ T cells (P = 0.007) and CD68+PD-L1+ cells (P < 0.0001) (Figure 2D & 2E).