I'm very sure that Russian and US militaries will not fight each other directly. If wars between nuclear states were possible, they would have already happened, and long ago. The US acquired nuclear weapons in 1945 and the USSR in 1949. There have been no direct confrontations since then, in spite of numerous changes of personnel at the top. That tells us that MAD is real and that policy-makers know it.
Proxy wars will continue though. The Korean, Vietnam, Central American, Afghanistan and lesser wars were the proxy wars of Cold War I. The South Ossetian, Syrian and Donbass Wars have been the proxy wars of Cold War II. The most likely theaters for new ones are the Caucasus, Central Asia, Latin America and the Middle East.
The Cold War is very unlikely to end in an assassination. Why do I say that? Because that's never happened before. If it could have, it would have. Some say that Stalin was poisoned but 74-year-old men have strokes all the time and, more importantly, the course of Cold War I was not affected by his death.
I know that globalism gobbled up Portugal in a 1975 military coup, but something like that is very unlikely in Russia. I have no idea what kind of people went into the military in 20th century Portugal, but Russian career officers tend to be conservative and patriotic. They're not going to mount any leftist coups.
I think that the likeliest end of Cold War II is the Gorby/Juan Carlos scenario. Putin's chosen successor or his successor's successor giving up the fight in order to seem cool, hip and like a forward-looking democratic reformer. The globalist brainwashing about what's cool and what isn't is as pervasive now as it was during Cold War I.
I should say that I'm pessimistic about the future of civilization in general, not just about the outcome of Cold War II. I'm guessing that China's and North Korea's sovereignty will eventually succumb to the same Gorby-like end. In Russia's case Gorby II will mean an orgy of looting and the further partition of the country.
One remote possibility that might prevent these apocalypses is what I'm going to call the Koba Effect.
Stalin signed up with the Communists in his youth because he was a Georgian nationalist. Koba, his early nickname, was a character in a Georgian nationalist novel. The Communists were plotting against Russia, which was patriotically-minded Georgians' chief enemy. The Bolsheviks used nationalist Georgians, Armenians, Poles, etc. as allies the same way that Western leftists use blacks, Hispanics and Muslims against Western countries' historical majorities.
But these minorities aren't really leftist. And neither was Stalin. When he came to power he turned the USSR in a deeply conservative direction. He ended up becoming the Old Bolsheviks' worst nightmare.
A future Western equivalent of the above could look like this: a leftist party in a major European country or even in the US could mominate a Muslim or a Hindu candidate for the top job. Just to rub some excrement in the majority's face. And he'd win. For the Koba Effect to work this person would have to come from a very clannish culture (Obama doesn't). I'm not saying that this will happen. But it could. And if it does, it could paradoxically help save civilization, or at least postpone its end.
All of my above musings about what could happen in the future are based on my understanding of what happened in the past. Aren't there any new tunes in politics? Sure, but they're usually introduced by technological change. Agriculture, metallurgy, firearms, the printing press, nukes and TV changed politics enormously. But for some reason the Internet hasn't. The direction and the speed of change of global politics are roughly the same now as they were before 1995, the year that Netscape made it big.
In the absence of new revolutionary technologies it's natural to expect the future to be a series of variations on the recent past.