We found that the supernatants from heated bacteria could more prominently activate STING pathway in macrophages than those from the same number of heated cells (Figure S31, Supporting Information) although the latter could also obviously stimulate STING pathway, suggesting that bacteria are mainly responsible for the activation of STING pathway in bacteria‐mediated PTT, but cellular DNA from destroyed cancer cells might also partially contribute to the activation. Here, STING1 is linked to cancer.