The aims of the current study were to (i) compare the in vivo efficacy of TH1902 in immunocompromised (TNBC MDA-MB-231 cells) and immunocompetent syngeneic mice models; (ii) evaluate whether TH1902 mobilizes the immune system against B16-F10 syngeneic tumors; (iii) investigate in vitro the cGAS/STING molecular events involved in the activation of defense immune mechanisms with regard to immune cell recruitment and tumor infiltration; and (iv) perform an in vivo efficacy study to assess the effects of combining TH1902 with anti-PD-L1 immunotherapy. Here, STING1 is linked to neoplasm.