Recent Advances in pH and Redox Responsive Polymer Nanocomposites for Cancer Therapy Cancer therapy is increasingly focused on personalized, targeted treatments. Stimuli-responsive biomaterials, such as pH- and redox-triggered polymer nanocomposites, are promising for site-specific drug delivery. These materials respond to the tumor microenvironment (TME), enhancing efficacy and reducing off-target effects. Cancer cells have unique properties, such as acidic cytosolic pH and elevated redox potential, which make them suitable targets. Functionalized polymer nanocomposites with large surface areas and specific targeting outperform conventional small-molecule materials. Multifunctional nanomaterials improve drug delivery to cellular or subcellular systems. Surface functionalization, site-specific targeting, and stimuli-responsive components enhance therapeutic efficacy. pH- and redox dual-stimuli-based polymeric nanocomposites for cancer therapeutics are scarcely reported. This review provides recent progress in pH- and redox-responsive polymer nanocomposites for site-specific drug delivery in cancer therapy. It explores design principles, fabrication methods, mechanisms of action, and prospects of these dual-stimuli-responsive biomaterials. Polymeric nanomaterials, including organic and inorganic nanoparticles, are widely used in cancer treatment due to their efficacy and versatility. They can be modified to incorporate stimuli-responsive signals, enabling precise drug release under specific conditions. Various strategies have been developed to generate stimulus-responsive signals in polymeric nanomaterials, including synthetic and bio-based polymers. These materials play a significant role in therapeutics by protecting delicate drugs until they reach their intended delivery sites. However, challenges such as physicochemical and biological obstacles hinder targeted delivery, drug solubilization, biocompatibility, and site-specific delivery to cells and tissues. Engineered or smart nanopolymer systems with dual-stimuli responsiveness, such as pH/magnetic fields, pH/redox potential, pH/temperature, and temperature/reduction, have been developed to address these challenges. Stimuli-responsive biomaterials are designed to detect and react to signals in the TME, allowing precise drug release. pH- and redox-responsive polymer nanocomposites have garnered attention for their dual-stimuli responsiveness and potential as future generation biomaterials. These nanocomposites respond to changes in pH and redox conditions, which are characteristic features of the TME. The slightly acidic pH of tumor tissues, resulting from increased metabolic rate and inefficient vascularization, serves as a distinctive trigger for pH responsiveness. At the same time, cancer cells have high amounts of reducing agents, such as glutathione (GSH), which makes redox responsiveness possible. The design principles of pH- and redox-responsive polymer nanocomposites involve incorporating pH- and redox-sensitive elements into a polymer matrix. These parts allow biomaterials to change their structure and physicochemical properties in a controlled manner when the pH and redox conditions change. This makes it easier forRecent Advances in pH and Redox Responsive Polymer Nanocomposites for Cancer Therapy Cancer therapy is increasingly focused on personalized, targeted treatments. Stimuli-responsive biomaterials, such as pH- and redox-triggered polymer nanocomposites, are promising for site-specific drug delivery. These materials respond to the tumor microenvironment (TME), enhancing efficacy and reducing off-target effects. Cancer cells have unique properties, such as acidic cytosolic pH and elevated redox potential, which make them suitable targets. Functionalized polymer nanocomposites with large surface areas and specific targeting outperform conventional small-molecule materials. Multifunctional nanomaterials improve drug delivery to cellular or subcellular systems. Surface functionalization, site-specific targeting, and stimuli-responsive components enhance therapeutic efficacy. pH- and redox dual-stimuli-based polymeric nanocomposites for cancer therapeutics are scarcely reported. This review provides recent progress in pH- and redox-responsive polymer nanocomposites for site-specific drug delivery in cancer therapy. It explores design principles, fabrication methods, mechanisms of action, and prospects of these dual-stimuli-responsive biomaterials. Polymeric nanomaterials, including organic and inorganic nanoparticles, are widely used in cancer treatment due to their efficacy and versatility. They can be modified to incorporate stimuli-responsive signals, enabling precise drug release under specific conditions. Various strategies have been developed to generate stimulus-responsive signals in polymeric nanomaterials, including synthetic and bio-based polymers. These materials play a significant role in therapeutics by protecting delicate drugs until they reach their intended delivery sites. However, challenges such as physicochemical and biological obstacles hinder targeted delivery, drug solubilization, biocompatibility, and site-specific delivery to cells and tissues. Engineered or smart nanopolymer systems with dual-stimuli responsiveness, such as pH/magnetic fields, pH/redox potential, pH/temperature, and temperature/reduction, have been developed to address these challenges. Stimuli-responsive biomaterials are designed to detect and react to signals in the TME, allowing precise drug release. pH- and redox-responsive polymer nanocomposites have garnered attention for their dual-stimuli responsiveness and potential as future generation biomaterials. These nanocomposites respond to changes in pH and redox conditions, which are characteristic features of the TME. The slightly acidic pH of tumor tissues, resulting from increased metabolic rate and inefficient vascularization, serves as a distinctive trigger for pH responsiveness. At the same time, cancer cells have high amounts of reducing agents, such as glutathione (GSH), which makes redox responsiveness possible. The design principles of pH- and redox-responsive polymer nanocomposites involve incorporating pH- and redox-sensitive elements into a polymer matrix. These parts allow biomaterials to change their structure and physicochemical properties in a controlled manner when the pH and redox conditions change. This makes it easier for