If you are trying to insert a roll that has a set name, you need to use the same syntax as the saving throws at the end. --Fort(@{selected|fortitude}),fortitude
Everything between the -- and , is the title that you click on. In that example, I have their fortitude bonus showing as part of the title. The bit after the , is the name of the button in the html. The easiest way to get this is to look at the wiki article for this sheet. The wiki article specifies how you can dynamically call roll buttons using the %{selected|rollbuttonnamehere} syntax. So, if they list the button you need, you can easily find the exact button name as specified in the html. The article (and relevant section) is here: <a href="https://wiki.roll20.net/Pathfinder_Official#Dynamic_Reference_to_Rolls" rel="nofollow">https://wiki.roll20.net/Pathfinder_Official#Dynamic_Reference_to_Rolls</a> So, it looks like you would want npc_cmb. That means your button would need to be something like this: --CMB(@{selected|cmb_mod}),npc_cmb I have not tested this, but that should work to trigger that roll.