he is working at a bank now 是现在进行时
他一直在银行上班 He has been working at a bank.更强调“一直在”
he has worked at a bank 也行.
+++++
he is working at a bank 他正在银行工作 （以前是否在那里工作没说明）
he has worked at a bank 他已在银行工作 （没有强调 “一直在”）