MAX22500/1/2 can operate up to 100Mbps. If using a general TVS, its junction capacitance is too high and will influence the high speed communication. Also, it needs to consider the clamp voltage to meet RS485 specification which has common voltage from -7V~+12V.
For this case, RCLAMP1224S.TCT is recommended. Its junction capacitance is 3pF max. only.
The RCLAMP1224S.TCT comes with two diodes in the opposite direction. To protect from both positive and negative ESD/surges, both of the diodes need to be connected in parallel and then to the line.
Pin 1, 6 are connected to the A or B. Pin 3, 4 are connected to ground.