Hi- I'm not an expert in the topic, but I know that the IPO is strongly related to the PDO.   The PDO is, in turn, significantly related to ENSO.  Tom wrote a nice blog post here describing the PDO and what influences it:

https://www.climate.gov/news-features/blogs/enso/going-out-ice-cream-first-date-pacific-decadal-oscillation

As for which PDO state we are in now, it's  uncertain.  Time series of the PDO show that we've recently returned to a slightly cooler-than-average state (it was warmer during 2015-16), but that could be because we had a La Nina last winter and we appear to be on the cusp of a La Nina this winter as well.