Many types of cancer are currently treated using a combination of chemotherapeutics, but unfortunately, this strategy is considerably limited by severe side effects. The current development of nanocarriers enables the use of multiple drugs anchored on one unique platform thus enhancing the initiated therapeutic effect and minimizing the possibility of drug resistance. In this context, a graphene‐oxide‐based 2D nanoplatform is developed, which is functionalized using highly branched polyethylene‐glycol and a multimodal set of two drugs with various mechanisms of action, namely Pt‐based complex (a Pt(IV) prodrugs based on cisplatin) and doxorubicin (DOX). We performed in vitro 2D screening on two cancer cell lines, namely glioblastoma and osteosarcoma, that were selected as models of two aggressive tumors that remain a massive challenge in oncology. The therapeutic effect of the developed nano‐platform is higher at lower concentrations (15 μ m of Pt‐drug, 0.6 μ m DOX) compared to the impact of the free drugs. This indicates a possible positive effect of the accumulation and transport of the drugs using this nanoplatform. Results obtained on 3D cell models using MG63 osteosarcoma cells uncovered an understandable lowered diffusion profile of the developed nanoplatforms, compared to the application of free drugs.