  We present a study by Scanning Tunneling Microscopy, supported by ab initio
calculations, of the interaction between graphene and monolayer
(semiconducting) PtSe$_2$ as a function of the twist angle ${\theta}$ between
the two layers. We analyze the PtSe$_2$ contribution to the hybrid interface
states that develop within the bandgap of the semiconductor to probe the
interaction. The experimental data indicate that the interlayer coupling
increases markedly with the value of ${\theta}$, which is confirmed by ab
initio calculations. The moir\'e patterns observed within the gap are
consistent with a momentum conservation rule between hybridized states, and the
strength of the hybridization can be qualitatively described by a perturbative
model.
