It is worthwhile to point out that vvDD combined with anti-PD-L1 Ab could elicit effective antitumour activity in the early-stage tumour model31, but not the late-stage tumour model, which suggests that only the appropriately armed oncolytic virus could effectively modulate the more immunosuppressive tumour microenvironment, as supported by other recent studies37,38. This evidence concerns the gene CD274 and neoplasm.