The discovery of XYZ exotic states in the hadronic sector, particularly those containing two heavy quarks, remains one of the most intriguing open problems in contemporary particle physics. In this work, we review how the Born–Oppenheimer effective field theory (BOEFT) provides a unified and systematically improvable framework for describing exotic hadrons with atleast two heavy quarks and arbitrary light degrees of freedom such as light quarks or gluons. The BOEFT construction is based on the nonrelativistic QCD expansion and exploits the scale separation and symmetries inherent in systems with two heavy quarks. The framework requires several inputs from lattice QCD. We apply BOEFT to study the spectroscopy of tetraquark and pentaquark candidates such as $\chi_{c1}{(3872)$, $T_{cc}(3875)^+$, $P_{cc}(4312)^+$, $P_{cc}(4380)^+$, $P_{cc}(4440)^+$, and $P_{cc}(4457)^+$, as well as their analogues in the bottom sector.