Photothermal treatment via Au NPs in the second NIR biowindow (NIR‐II) triggered more homogeneous ICD in deeper tumor tissues compared to the first NIR biowindow (NIR‐I) (Figure 8b,c).[151] They systematically investigated the underlying immune mechanism: various DAMPs like ATP, CRT, and HMGB1 were secreted from cancer cells after NIR‐II laser irradiation; NIR‐II PTT‐induced ICD facilitated the maturation of DCs and proliferation of CD8+ T cells (Figure 8d,e). The gene discussed is HMGB1; the disease is cancer.