Necessity of an Inductor at CAN Transceiver end
what is the necessity of an inductor (L310) between CAN transceiver
  and physical CAN line


L310 and the two 220 pF capacitors form a common mode filter so that common mode interference on the line (to the left) is not transferred at the same magnitude to the chip on the right.

If you can provide a data sheet for L310, more information can be provided.