Tumour models were established by subcutaneous injection of the MC38 colon adenocarcinoma cell line in a homozygous mouse model. Mice were treated with a DC1–DLK1 vaccine in combination with anti-PD-1 antibody to enhance efficacy. Vaccine-induced immune responses and anti-tumour effects were assessed by flow cytometry, immunohistochemistry, immunofluorescence, and quantitative PCR. Here, DLK1 is linked to neoplasm.