***The same thing: they are both monotheistic religions, they all have a general religious classic, they all promote some kind and tolerant content, they are both mainstream religions in the world, they are widely spread, and their doctrines have also undergone many changes.
Difference: Islam prohibits idol worship, which is why there are basically calligraphy works in the mosque. Idol worship is prevalent in Christianity, with many worshipers of Jesus, the Virgin, angels, etc.
The establishment of Islam was influenced to a certain extent by Christianity.
Islam has a well-organized society and strict religious rules. Not so with Christianity.