Disclosed are oncolytic viruses comprising chimeric human/mouse CD40 ligands. The chimeric human/mouse CD40 ligand may be MEM40. The oncolytic virus may be replication competent. The oncolytic virus may be an oncolytic herpes simplex virus. Also disclosed are methods comprising administering an oncolytic virus armed with at least one chimeric human/mouse CD40 ligand, for example MEM40, to a patient suffering from cancer.