Interaction between two hadrons in lattice QCD

I report recent developments on hadron interactions in lattice QCD by the HAL QCD method. As an introduction, I summarize the lattice community's consensus on the absence of the deeply bound dinucleons at heavier pion masses. We then present 4 results by the HAL QCD method using $2+1$ flavor QCD gauge configurations at $m_\pi \simeq 146$ MeV and $a\simeq 0.0846$ fm, which are the $\Lambda\Lambda-N\Xi$ interactions, $N\Omega$ dibaryon, the tetra-quark state $T_{cc}$ and the $N-\phi$ interaction with the 2-pion tail. A brief summary follows.