In recent years, cancer therapy has witnessed significant advancements, with a focus on personalized and targeted treatment strategies. One promising approach involves the use of stimuli-responsive biomaterials for site-specific drug release. Among these biomaterials, pH, and redox-triggered polymer-nano composites have gained immense attention due to their ability to respond to the specific tumor microenvironment, enhancing therapeutic efficacy while reducing off-target effects. Cancer cells often exhibit anomalous biochemical properties, attributed to lower cytosolic pH (acidic) and elevated redox potential through the epitomized upregulation of undesired genes. Such biological process substantially imbalance the level ions (protons) and biological thiols glutathione (GHS) in the cytoplasm as well as in the subcellular organelles. Superfluous accumulation of ions and redox imbalance is associated with proliferation, invasion, and growth of tumor. Because of high surface area, deep tissue penetration capability, higher hydrophilicity, hydrophobic interior for drug/gene efficient loading, biocompatibility and site-specific targeting efficiency, functionalized polymer nanocomposites are superior to conventional small molecular materials. Paradoxically conventional methods of drug delivery aided therapeutics accompanied with inherent drug/genes are encapsulated in biocompatible carrier or suitable transfecting agents generally suffered with low bioavailability, uncontrolled drug release, low cellular penetration, cellular internalization, toxicity, and poor drug loading efficiency. To overcome these issues, recently various multifunctional nanomaterials were developed, based on synergistic stimuli responsive aided drug release in a specified cellular or subcellular system. High therapeutic efficacy, of nanoparticles (NPs) mainly associated with surface functionalization through biocompatible polymeric materials, site-specific targeting units accompanied with stimuli responsive components. Followed by therapeutically important drug or genetic materials were loaded into NPs either in covalent or non-covalent approach. Intriguingly, combined pH and redox dual stimuli based functional materials specially based on polymeric nanocomposites for cancer therapeutics scarcely reported. This article provides the recent progress in pH and redox-responsive polymer-nano composites for site-specific drug delivery in cancer therapy. It explores design principles, fabrication methods, mechanism of action, and prospects of these dual-stimuli responsive biomaterials.