Those who turn their back on Islam are to be executed. This is CONFIRMED by the words and deeds of Muhammad. The only freedom of belief in Islam is the freedom to become Muslim.

The most reliable hadith collection contain numerous accounts of Muhammad and his companions putting people to death for leaving Islam.

Islamic Law:
There is also a consensus by all four schools of Sunni Islamic jurisprudence (i.e., Maliki, Hanbali, Hanafi, and Shafii), as well as classical Shiite jurists, that apostates from Islam must be put to death. The process of declaring a person to be an apostate is known as takfir and the disbeliever is called a murtad.

https://www.thereligionofpeace.com/quran/bukhari/089-sbt.htm#009.089.271
https://www.thereligionofpeace.com/pages/quran/apostasy.aspx