What Smart Data Mode feature indicates for iPhone?

Anyone having idea: what Smart Data Mode feature indicates for iPhone?
Is it specific to 5G or LTE?

Not aware about 4G, but it impacts in 5G.

Like do SgNB release in case of UE is heated and others.

Ok thanks. So it’s linked to overheating in iPhone.
To release SCG cell.
Like Samsung Exynos.