Multiwavelength SED of LHAASO J2108+5157 showing a leptonic scenario of emission. Observations with different instruments are represented by data points of different colors: XMM-Newtonr = 6′ (blue), r = 16′ (green), Fermi-LAT (red), LST-1 (purple), and LHAASO-KM2A (yellow). The black solid line represents the best-fitting IC-dominated emission of LST-1 and LHAASO data. The corresponding synchrotron radiation of the same population of electrons is represented with dashed and dash-dotted lines for B = 1.2 μG and B = 1.9 μG, respectively. The dotted line represents a phenomenological model of a tentative pulsar: the best-fit PL with a subexponential cutoff on the Fermi-LAT data.