Can anyone please help me find this manga?? Okay so the cover has the mc the art is a bit ...

Can anyone please help me find this manga?? Okay so the cover has the mc the art is a bit realistic and the mc is a middle age man with glasses. The story is about retired/ secret/ on a break spy or assassin or military people. I don't really remember anything more about it (it's not fantasy or Isekai) it's more on action no romance! Please help me find it