To integrate the key concepts of this review, Figure 1 provides a one-page schematic of our conceptual framework and novelty: nanoparticle (NP)-mediated delivery of STING agonists directly targets the cGAS–STING axis and is combined with PD-1/PD-L1 blockade (±other adjuvant therapies) to elicit synergistic anti-tumor immunity. The gene discussed is CGAS; the disease is neoplasm.