The aim of the game is to respond to the player above with the winner and reasoning. You don't have to go into the depth I did in the example, I got carried away. The teams should be in a video game, but I'm fine with characters from most fictional works (so long as a quick wikipedia will give you enough information about them to assess who would win). Most mainstream things are fine, but no ISIS vs Al Qaeda - grade stuff.
For example
Player 1: Blue team from the HALOverse versus all the main characters from the CODverses. They would all be armed with standard-issue weaponry; MAG5 assault rifles + Magnums (The HALO:CE ones) and of course their suits. The MCs from COD would be armed with their standard armor and weaponry, or standard-issue gear (M4 carbines SOPMOD)
Player 2: I think that Blue team would win because, despite an overwhelming numerical disadvantage, the Spartan IIs were trained as soldiers at the age of six, and if they all aged and no-one died until this theoretical encounter, they would be biologically about 41 years old; 35 straight years of combat. Therefore the Blue Team has the advantage of experience. Equipment is another factor. Barring AW Lasers, nearly all COD weapons would have trouble penetrating MJOLNIR armor. MJOLNIR armor gives Chief the equipment he needs to flip a Scorpion tank right-way-up, giving the Spartans a lot of brute strength. AW lasers would be the most feasible option to kill Blue Team, after the MJOLNIR energy shields get worn down.
Now let's move on to CQC, as previously stated, Blue team has enough strength to flip a tank, and knives to boot. The Spartans would win in CQC nearly every time.
Another issue that the MCs from the CODverse would face is trust. Assuming that Makarov and Price could get their shit together and fight side-by-side, there would still be trust issues between them, further destabilising leadership. Leadership is another point: Blue team has a clearly defined leader (Master Chief) whereas the CODverse has many factions with many leaders, and all thrown into the same team, there would likely be a power struggle for 'supreme commander'.
The only way I can see the CODverse winning is by leading the SPARTANs to water and drowning them/starving them. The MJOLNIR suits are heavy and dense enough to sink. Swimming in regular boots is hard enough in real life, imagine trying to do that in ultraheavy power armor. After the Spartan's air supply runs out, they would suffocate.
My scenario is: Armok vs Thor?
OK, so now that the Examples are done, let's get to it.
Scenario: Scorpion Main Battle Tank from HALO (piloted by marines trained to operate it) vs Tiger II (War Thunder, COD, Brothers in Arms, take your pick) (Piloted by trained Panzer Crew of WW2). This assumes that the Scorpion has been taken to WW2-era times. Take your pick of WW2 battlefields