This work proposes a testable hypothesis linking superconducting and thermoelectric behavior in Tl-doped PbTe through strong electron–phonon coupling.Building on established resonant-level thermoelectric models, we suggest that the same coupling responsible for superconductivity in PbTe:Tl (λ ≈ 0.5–1) may also produce observable Migdal–Eliashberg–type signatures in the thermoelectric regime.Using the Migdal–Eliashberg framework, we outline specific, falsifiable experimental predictions—magnetic-field-dependent Seebeck suppression, concentration-dependent phonon softening, and spectroscopic mass enhancement—and define quantitative criteria to confirm or rule out Migdal contributions.The goal is to determine whether strong-coupling effects, beyond conventional resonant scattering, influence thermoelectric transport in PbTe:Tl and related chalcogenides.