Provided are immunostimulatory bacteria and oncolytic viruses, and pharmaceutical compositions containing the bacteria and/or viruses, that act as three prime repair exonuclease 1 (TREX1) antagonists. The bacteria and viruses are for treating tumors that are human papillomavirus (HPV) positive or that have a high tumor mutational burden (TMB). The immunostimulatory bacteria and oncolytic viruses encode therapeutic products such RNAi, such as shRNA and microRNA, that mediate gene disruption and/or inhibit expression of TREX1, or that inhibit TREX1. The bacteria contain additional modifications to enhance their anti-tumor activity. The bacteria and viruses are used for treatment of tumors in which TREX1 expression correlates with the presence of the tumor or properties of the tumor, such that inhibition of TREX1 advantageously treats the tumor.
