The efficacious delivery of therapeutic nucleic acids to cancer still remains an open issue. Through the years, several strategies are developed for the encapsulation of genetic molecules exploiting different materials, such as viral vectors, lipid nanoparticles (LNPs), and polymeric nanoparticles (NPs). Indeed, the rapid approval by regulatory authorities and the wide use of LNPs complexing the mRNA coding for the spark protein for COVID‐19 vaccination paved the way for the initiation of several clinical trials exploiting lipid nanoparticles for cancer therapy. Nevertheless, polymers still represent a valuable alternative to lipid‐based formulations, due to the low cost and the chemical flexibility that allows for the conjugation of targeting ligands. This review will analyze the status of the ongoing clinical trials for cancer therapy, including vaccination and immunotherapy approaches, exploiting polymeric materials. Among those nanosized carriers, sugar‐based backbones are an interesting category. A cyclodextrin‐based carrier (CALAA‐01) is the first polymeric material to enter a clinical trial complexed with siRNA for cancer therapy, and chitosan is one of the most characterized non‐viral vectors able to complex genetic material. Finally, the recent advances in the use of sugar‐based polymers (oligo‐ and polysaccharides) for the complexation of nucleic acids in advanced preclinical stage will be discussed.