Metal‐based smart nanosystems show great potential in modulating each phase of the cancer immunity cycle to boost anticancer immune responses against tumor growth, recurrence, and metastasis mainly by inducing immunogenic cell death, repolarizing protumoral M2 tumor associated macrophages(TAMs) into antitumoral M1 phenotype, and activating the cGAS‐STING signaling pathway. This evidence concerns the gene CGAS and cancer.