What is the structure of CF3 radical?
CH3 radical is Sp2 hybridised carrying the lone electron in a pure p orbital. This is so because Sp2 hybridised orbitals are lower in energy than Sp3 hybrid orbitals (The more the S character the lesser is the energy of the orbital). When there is a lone electron present, it is more efficient to keep the bond pair electrons in lesser energetic Sp2 hybrid orbitals and lone electron in higher energy pure P orbital than keeping all bonding pairs and the lone electron in Sp3 hybrid orbitals. So most of the radicals are Sp2 hybridised.

But in situations like •CF3 where the atoms/groups attached to C are of high electronegativity things may change. According to Bent's rule more electronegative atoms/groups will favour less electro negative orbitals i.e. orbital s with lesser s character(Sp3 has lesser S character compared to Sp2). This is quite obvious because the more the S character of the C center the more is the tendency of the C center to attract the bond pair towards itself and in cases like electronegative atom, it will also try to attract the bond pair towards itself. This makes some unhappy situation. This is reflected by the Bent's rule. That is why •CF3 radical favours Sp3 hybridisation.

It's not that only such radicals like •CF3 can acquire Sp3 hybridisation. In many other cases like bridge head of adamentum also acquire Sp3 hybridisation becauseof opposition by its rigid structure to acquire planarity on generation of radical though it's not that much easy process to form radical here.

In conclusion, a radical will favour that hybridisation which will be energetically favourable for it.