It has been under discussion for a long time, it's just a hard nut to crack with a lot of ideas not working as well as you would think.
Previously not really much you could do against enough suicide bombers, but was mitigated by most people not wanting to die. Not with uncrewed systems that's pretty much out the window.
Improving detection times helps though, so the various IR/visual sensors with some algorithms help with things that don't have a radar or other signal signature.
Always the old school ideas too like torpedo nets; that way at least gives you a standoff from the blast with retractable physical barrier.
Torpedo net - Wikipedia