The present disclosure relates generally to the fields of oncology, virology and immunotherapy. It concerns poxviruses, specifically the highly attenuated modified vaccinia virus Ankara (MVA), and a recombinant modified vaccinia Ankara virus with deletion of vaccinia virulence factor E3 (MVAΔE3L), each further modified to express human Fms-like tyrosine kinase 3 ligand (Flt3L) or GM-CSF. The disclosure relates to use of the foregoing recombinant viruses as cancer immunotherapeutic agents. The foregoing recombinant poxviruses can also be used in combination with immune checkpoint blockade therapy.
