  We study a class of models in which the Higgs pair production is enhanced at
hadron colliders by an extra neutral scalar. The scalar particle is produced by
the gluon fusion via a loop of new colored particles, and decays into di-Higgs
through its mixing with the Standard Model Higgs. Such a colored particle can
be the top/bottom partner, such as in the dilaton model, or a colored scalar
which can be triplet, sextet, octet, etc., called leptoquark, diquark, coloron,
etc., respectively. We examine the experimental constraints from the latest
Large Hadron Collider (LHC) data, and discuss the future prospects of the LHC
and the Future Circular Collider up to 100TeV. We also point out that the
2.4$\sigma$ excess in the $b\bar b\gamma\gamma$ final state reported by the
ATLAS experiment can be interpreted as the resonance of the neutral scalar at
300GeV.
