The planets are part of the galaxy.
There are no known planets in any galaxy other than our own. While it is doubtless that other galaxies, including the cigar galaxy, contain planets they are much too far away fur us to detect them.
It is extremely likely, but we cannot yet find planets from that far away. All the planets we have found to date are in our own galaxy. The Andromeda galaxy is 2.5 million light years away whereas our galaxy is about 100,000 light years across.
That is very likely, although for obvious reasons, all planets discovered so far (or most of them?) are in our own galaxy.
No planets have been officially recognised outside our galaxy, though more than 500 exoplanets have been identified outside our solar system. Our nearest galaxy is too far away to detect such planets, though we can assume that it will contain several millions of planets based on observations within our own galaxy.
A galaxy is far larger. A planetary system involves one or more planets revolving around a single star. A Galaxy consists of billions of stars.
It is possible that every galaxy has some planets. We just are starting to detect some planets in other galaxies.
The planets we know of, some 300 now, are all in the Milky Way galaxy.
Planets are not necessarily in a galaxy but chances are very slim that in a galaxy that is not just newly forming there would not be any exoplanets.
We expect the Andromeda galaxy to be just like our own Milky Way galaxy. We can see stars (suns) in the Andromeda Galaxy and just as stars have planets orbiting them in our galaxy, we believe that there must be planets also orbiting stars in the Andromeda galaxy.
The Andromeda galaxy is a separate galaxy from our Milky Way and has its own set of planets. However, due to the vast distance between our galaxies, we are currently unable to observe individual planets in the Andromeda galaxy.
Nothing from another galaxy can affect Earth ever. Other galaxies are too far away.
There is not much solid information known about planets in other galaxies. Most planets discovered so far are in our own galaxy. This is because it is easier to discover a relatively near-by planet than one that is much farther away. However, the planets found so far make it likely that in our own Milky Way, and therefore other galaxies as well, have at least as many planets as stars.