Last week saw an apparently important jobs report ATTEMPT to have a lasting impact on financial markets only for the move to be completely erased by this morning.  Labor market data was already a bit of an outcast owing to its consistently strong performance in recent months/years (i.e. labor market strength is the rule, not the exception.  Therefore, the strong report is less of a surprise and thus less of a market mover).   

But if we could only pick one reason for markets to ignore jobs data (or MOST data for that matter), it's the uncertain economic implications of an eventual trade deal.  That also helps explain all of today's intraday volatility as bond yields were bumped up early in the domestic session by one batch of headlines and then again about an hour later by another batch of headlines.  The moves weren't huge, but they were the only detectable instances of cause & effect between data/headlines and market movement.

We should mostly expect tomorrow's Fed announcement to have its thunder stolen in the same way.  That's not to say the Fed doesn't matter--just that it matters much less than normal right now.  The case for such claims is only strengthened by the fact that the Fed is almost 100% certain to keep rates unchanged tomorrow.  As such, the extent of the impact would have to come from verbiage changes or interpretations of changes to the Fed's rate outlook.  Both would have to be taken with a grain of "uncertainty salt" due to trade negotiations.