Ice ⇌ water .
According to Le-Chatelier's principle, at equilibrium, if we change temperature or pressure of a reaction it will shift in such a way so as to undo the change.
Melting of ice is endothermic process, so supply of heat shifts equilibrium in forward direction.
Volume of ice is more than volume of water, so increase in pressure shifts equilibrium to right.
High temperature and high pressure are favourable conditions of melting of ice.