If your setting allows it you can make the range of weapons an issue.
That would decrease the necessity of cover depending on the enemies setup.
It also provides more variety to play styles as players can go high risk high reward or play it safe from far away.
A unit can have its own cover (to a specific direction), for example a tank or riot shield guy.
Players would need to take into account facing direction and action cost for maneuvers.
Expanding from that idea you can have certain units which provide cover or defensive bonuses to teammates.
This would be for example some kind of energy shield in various shapes and colours.
It would also increase the synergy between the team members.
The alternative to cover would be having some kind of unit who just can take a lot of damage.
If your units are puny humans that probably is scifi/fantasy material, though.