2 Channel Stereo Audio Mixer - 3.5mm Mini Mixers Audio with Dual Volume Control Knobs, Aluminum Shell, 2 in 1 Out Small Audio Switch for PC Headphone Speaker Monitor Projector Live Streaming

You cannot use a passive cable. If all three devices have analog connections, a small mixer like this might work: https://www.amazon.com/Channel-Stereo-Audio-Mixer-Headphone/dp/B0GDXRZX4G/ref=sr_1_9_sspa You will need to provide a power source to operate the mixer.