Immune checkpoint PD-L1 (programmed cell death-ligand 1) expression was also significantly upregulated in AT3 tumours from mice treated with the combination of olaparib and AZD1775 compared with those from the monotherapy and vehicle treatment groups which is suggestive of the presence of immune suppression via the PD-1/PD-L1 pathway despite the immunogenic microenvironment induced by the combination treatment. Here, PDCD1 is linked to neoplasm.