We present the numerical investigation of the phase change material and MXene-based wide range refractive index sensor for the visible and infrared spectrum. The proposed structure is investigated in three layered structures, consisting of layers of Ge2Sb2Te5, Ti3C2TX, silica, and silver materials. We have presented the reflectance response of these multi-layered structures for refractive index ranges 1–2.2. The overall design is simulated using the finite element method of computational technique. We have also investigated the effect of different material heights on the overall performance of the structure. We have presented several resonating trace equations to identify the sensing behaviour for a specific wavelength range and refractive index values. The proposed design is also investigated for the different oblique angles of the incident condition to identify the wide-angle stability of the proposed structure. Numerical investigation of the proposed structure can help to design biosensors to detect a wide range of biomolecules such as cancerous, haemoglobin, urine, saliva-cortisol and glucose.