please help me to find schematic function

Dear all :
please help me to find schematic function
between signal input to RF_IN_A .
It's a attenuation or matching or .......

Thanks.

Assuming that signal input is also 75 ohms and MMCX is high impedance, this is a 1MHz cut-off High Pass Filter with 4dB inband insertion loss and more than 40dB rejection at 10kHz.

May I ask from where the "input signal" is coming from or going out?
It will be helpful if given brief application.

This is an equalizer. Simulate and you'll see that the input and output match are perfect, but the S21 is slightly rising with frequency.