Hello @RedPanda, there are people who claim to be "Christian" strippers, "Christian" prostitutes, "Christian" pantheists, etc., so why not "Christian" witches too That said, claiming to be a Christian doesn't make one a Christian (even if they truly believe that what they are claiming is true, sadly).
Here are some NT verses that come to mind concerning this (so, what the OT taught appears to be confirmed as still valid by the NT).
Galatians 5
19 The deeds of the flesh are evident, which are: immorality, impurity, sensuality,
20 idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, disputes, dissensions, factions,
21 envying, drunkenness, carousing, and things like these, of which I forewarn you, just as I have forewarned you, that those who practice such things will not inherit the kingdom of God.
Revelation 21
8 The cowardly and unbelieving and abominable and murderers and immoral persons and sorcerers and idolaters and all liars, their part will be in the lake that burns with fire and brimstone, which is the second death.
God bless you!
~Deut