Weather radar might be an idea - provided the fighter has the appropriate equipment, fitted with the appropriate database....
Fighter jets cannot operate with TCAS, because from the beginning to the end of their flights, they are doing rejoin or intercept manoeuvres between themselves, or the tanker, or even some liner they are missioned to identify...
so their flights would be a nightmare of RAs from the beginning to the end
and even without that, just one of them pointing his nose towards you in a perfectly safe manner, miles away but at 450/500 kts, would generate enough RA and reports to spend one hour after each flight filling the reports...
Also space and weight are at a premium in a fighter jet (you already have to bargain for a 20 kg ECM device which will save the day out in operations)
Just remember that for the fighter, you are motionless in the sky -- so HE will avoid you- please do nothing...