Recent measurements by CMS and ATLAS at the LHC have independently revealed an intriguing excess near the top quark–antiquark production threshold. In this seminar, I will present the CMS analysis in the dileptonic channel based on the full Run II dataset. The observed excess is compatible with contributions from a short-lived ¹S₀ quasi-bound state (“toponium”), but can also be interpreted in terms of heavy scalar or pseudoscalar resonances. A comparison with the ATLAS result and prospects for clarifying the origin of this enhancement in future measurements will be discussed.