Alright since no one answered I’ll offer my two cents.
The two most significant combos with cable, and worth learning, are as follows:
cr.lk, cr.lk, hk, tiger-knee AHVB. (AHVB means Air Hyper Viper Beam. It’s done with a tiger knee motion :down to up-forward:. You should see the super jump splash and have the super come out immediately.)
HP x 4, lp skimitar, AHVB. The skimitar is cancel-able into super, so this combo gives you a way to link multiple AHVBs from full screen.
Zoning:
Standing fierce is really good to put the pressure on from full screen. If you have them in block stun, canceling with almost any of cable’s specials (grenade, lp.skimitar, lp.viper beam, psy-charge) is better than letting the move recover on its own. Be careful about using hp. viper beam because a lot of characters can punish it.
If they jump over your standing fierce you have three options. lp. skimitar is the most offensive of these and keeps the pressure on really well, especially against characters without multi-jump or airdash. psy-charge is good because it has less recovery and allows you to move cable faster than letting HP recover on its own. Grendade is the most defensive option. Make sure that, no matter which version you use, you hold the button in and release it on your own. If you do it like that, you can have the grenade detonate right above cable’s head, which is a great defensive tool against enemies who are coming in overhead. If you don’t hold the button in the grenade with detonate mid-screen.
Misc:
In practice mode, get your guard breaks down to a science. Put the CPU in normal jump mode and practice hit-confirming guard breaks. If you didn’t know, Marvel limits characters in normal jump mode to one guard action. So if you hit a character at the peak of their jump with a gunshot and wait half a second, you’ll be able to AHVB them.
Last, keep in mind that Cable is a threat any time he has three bars. Practice comboing three AHVBs in practice mode (It might be tough, but with enough practice you’ll get the timing down to combo 4. Against big chracters like Sent and Blackheart you should be able to combo 5 no problem.) If cable has 3 bars he’s a mortal threat to most assists: if your opponent calls an assist out, hit them with three AHVBs but DON’T do it as quick as you would against a point character. This is because combos can be reset for more damage against assists just as combos can be reset against point characters.
Hope that gets you guys started.