Dell Inspiron 15 3530 has keyboard backlit?

Not as standard equipment, no -- the base systems come with a non-backlit keyboard.  Use the service tag at dell.com/support to look up the specifications on  your specific system to see what type of keyboard it has.

If you are customer and shopping for a new Inspiron 15 3530, this SKU will have backlit keyboard https://www.dell.com/en-us/shop/dell-laptops/inspiron-15-laptop/spd/inspiron-15-3530-laptop