Transition metal dichalcogenides (TMDs), the class of 2D materials with a structural formula MX2, recently attracted increased attention because of the possible applications of these layered materials in different areas ranging from catalysis and sensing to opto-spintronics. (1−6) In the case of MoS2, which is a representative example in this class of materials, with a band gap of 1.8 eV, two spin–orbit split valleys at the K and K′ points have opposite spins (7) that can be detected either in circular dichroism experiments or using spin-resolved photoelectron spectroscopy. (8−12) Several ways to control spin-polarization of the respective spin–orbit split states at K and K′ were proposed, like external magnetic field, (13−15) magnetic impurities in single- or multilayer MoS2, (16,17) defects engineering, (18,19) or via proximity with ferromagnetic or antiferromagnetic materials. (20−22) In the later case of the MoS2/YIG system (YIG is the yttrium iron garnet magnetic insulator), it was found that the magnetic proximity effect disappears at distances more than 5 Å with antiferromagnetic coupling at the interface between two materials. (20) The effective charge transfer of spin-polarized electrons was found, however, without hybridization of the electronic states at the interface. Recently, several experimental works appeared in the literature, which aimed in the controllable epitaxial growth of TMDs layers on metals, like Au(111), (23,24) or insulating substrates, like sapphire. (25) Further works demonstrated the successful decoupling of TMDs, particularly of MoS2 from metallic substrates using graphene (gr) as an intermediate layer. (26) A similar approach was suggested for the growth of MoS2 on graphene prepared on ferromagnetic Co. (27) In this work, the CVD grown gr/Co(0001) system was used as a support for the deposition of the Mo layer, and then, the sulfurization of this layer at 600 °C should lead to the formation of MoS2 on gr/Co(0001). Despite the simultaneous intercalation of S atoms in the gr/Co interface during formation of MoS2, as confirmed by the respective angle-resolved photoelectron spectroscopy (ARPES) experiments, and the large distance of ≈8–9 Å between magnetically dead Co interface atoms and Mo atoms, which are magnetically screened from Co by graphene layer and S atoms, the sizable exchange spin-splitting of the MoS2 energy bands at the Γ point of ≈20 meV is found at room temperature, confirmed also by the density functional theory (DFT) calculations. If one assumes that the same empirical rule for the magnetic moment of 3d metals (1 eV of the exchange splitting of the 3d states near the Fermi level approximately corresponds to the 1 μB of the local magnetic moment) (28,29) is also valid for the magnetic state of 4d atoms, then the induced magnetic moment of the 0.02 μB/Mo atom is expected for MoS2 grown on a gr/Co(0001) substrate. Such results lead to the estimation of the effective magnetic field produced by the gr/Co substrate of ∼100 T. The obtained values for the magnetic moment in MoS2 are comparable to the induced magnetic moment of carbon atoms in graphene (0.05–0.1 μB), which, however, was found in much closer proximity to ferromagnetic Ni, Fe, or Co at the distance of ≈2 Å, where the effective hybridization of the electronic states and charge transfer at the interface were found. (30−32) Therefore, systematic studies and analysis of the observed effects for the MoS2/gr/Co(0001) system where interaction between layers is of van der Waals origin are required in order to shed more light on the mechanism causing the respective observed magnetic phenomena. Here, we present systematic, realistic large-scale DFT studies of different layered systems combining MoS2 and graphene layers on ferromagnetic Co(0001). In order to correctly describe the complete set of experimental data (observed p-doping of a graphene layer), we considered large-scale epitaxial systems corresponding to the respective periodicities of the MoS2 and graphene layers, and additionally, the effect of intercalated S atoms in the gr/Co(0001) interface with distributed S atoms or formation of the CoSx layer was taken into account. Our results unequivocally demonstrate that, taking into account all experimental observations, only MoS2/gr on Sint/Co(0001) correctly reproduces the obtained results. It is also demonstrated that in all considered cases the exchange spin-splitting of energy bands and the induced magnetic moment in MoS2 are absent and not reproduced in realistic DFT calculations. The absence of the claimed effects is clearly explained by the van der Waals origin of interactions in the considered systems at the large distances between weakly coupled graphene and MoS2 layers and by the screening effect caused by graphene and S atoms for the strongly reduced magnetic moments of the interface Co atoms. The presented results point to the importance of the careful analysis of the presented experimental data, which might be of importance for further studies of different layered heterostructures.