The presence of DNA in the cytosol triggers a protective response from the innate immune system. Cyclic GMP‐AMP synthase‐stimulator of interferon genes (cGAS–STING) is an essential cytosolic DNA sensor that triggers a potent innate immune response. As a result of this signaling cascade reaction, type I interferon and other immune mediators activate an immune response. The cGAS–STING pathway has great anticancer immunity‐boosting potential since it produces type I interferons. The detection of double‐stranded DNA (dsDNA) in response to various stimuli initiates a protective host's cGAS–STING signals. So, it is clear that a substantial relationship is expected between cancer biotherapy and the functioning of the cGAS–STING pathway. Several STING agonists with promising outcomes have been created for preclinical cancer therapy research. Notably, immunotherapy has dramatically extended patient survival and radically altered the course of lung cancer treatment, particularly in more advanced instances. However, this method is still ineffective for a large number of lung cancer patients. cGAS–STING can overcome resistance and boost anticancer immunity by stimulating the activity of many pro‐inflammatory mediators, augmenting dendritic cell cross‐presentation, and initiating a tumor‐specific CD8+ T cell response. This review aims to present the most recent results on the functionality of the cGAS–STING pathway in cancer progression and its potential as an immunotherapy target, with a focus on lung cancer.