Spiral leadin is what you want to use. That will cause the tool to ramp in. I use 0.5 to 10° spiral angle depending on the work. Press the ALT key and you can rotate the part around on the screen to look at the tool path in 3D. If the leadin angle is not what you want, change it, and generate toolpaths again.
Tangent leadin/out will move the tool into/out of the work on an arc. Useful for minimizing tool marks on the finish cut and plunging in air where you can use it.