How to use PS to make the atmosphere of a photo dull?

Select the layer you want to change, press "q" to enter the quick mask, and then use the brush tool to draw people. Press "Q" to return to normal mode after drawing, and you will find that all areas except the characters are selected, then set the foreground color to white and the background color to black, then press Ctrl+Alt+d to feather, and the feather value is set to 10, and then press Delete according to the actual effect you see.