“…Internal stimuli‐responsive strategies have recently gained great attention in the field of cancer management for their unique advantages as release of tumor‐specific imaging reporters/drugs in response to the physiochemical and abnormal physiological condition of tumor microenvironments and tumor cells, such as a low pH (Mi et al, 2016; F. Wang, Wen, et al, 2020), tumor hypoxia (Yuan et al, 2017), as well as a high level of intracellular glutathione concentration (S. Guo, Xiao, et al, 2019; M. Li, Zhao, et al, 2019), intracellular reactive oxygen species (Y. Wang, Li, Du, & Liu, 2020; X. Yang, Hu, et al, 2019), and tumor‐specific enzymes (Cai et al, 2020; K. Chen, Cai, et al, 2019; R. Liu, Hu, Yang, Zhang, & Gao, 2019; Z. Luo, Dai, & Gao, 2019). Correspondingly, a set of internal‐stimuli responsive bonds have been extensively explored, including pH‐responsive bonds (hydrozone, acetal, cis‐acotinyl, and boronate ester), reduction‐responsive bonds (i.e., disulfide, diselenide), oxidation‐responsive bonds (selenide), and enzyme‐responsive bonds (substrates for specific enzymes) (Cai et al, 2018; Chen et al, 2020; C. Guo, Sun, et al, 2017; Qiu, Cheng, Zhang, & Zhuo, 2018; Mi, 2020).…”