Why do people convert from Christianity to Islam?

For several reasons and generally the same reasons most people convert to any other religion.

Some people convert for their significant other. So they can get married or maintain a household religion for their family.

Just as there are born again Christians who come to the faith, you have people to come to faith later in life to other religions.

For majority of the "main line" religions rooted in Jerusalem there are dozens of similarities and crossroads where they converge or intersect. They share in many of the same stories, people, places and events but from different perspectives, and points of view which changes how their religion worships and function.

Perhaps they are people looking for answers to questions that have no answers.

Same reason some people follows blindly the orange cult...