Iron abundance versus [α/Fe] for stars in the HARPS GTO program. The position of TOI-3568 is marked by a blue star (differential abundances) and by a green star (nondifferential abundances). The black dashed line separates the galactic thin-disk (bottom) and thick-disk populations (top). For comparison, we also include the bona fide thick-disk stars with transiting planets Kepler-444 (Campante et al. 2015), TOI-561 (Weiss et al. 2021), K2-111 (Mortier et al. 2020), and WASP-21 (Bouchy et al. 2010).