In the Pro 3.5 release, it will be possible to configure the line chart marker symbol and size, so you'll be able to hide the markers by setting the size to zero.
I noticed this is also tagged with "elevation profile". Just to be clear, the 3.5 enhancement for configuring marker size is only for line charts (as well as scatter plots and combo charts). Elevation profiles do not show any point markers except the pointer/mouse location. Was this what you were referring to?
