In terms of the season overall, you’re seeing two teams who did much better last year (7th for West Ham, 8th for Leicester) than they are currently doing this year, so there’s that tension in both fan bases. They’re in somewhat opposite form right now, West Ham has lost three of their last five, Leicester has won three of their last five.
If the teams below them do well enough, it’s theoretically possible that either team could end up in the relegation zone by the end of the day. That’s the bottom 3 teams in the league, who at the end of the season are booted out of the Premiere League and into the next lower league, in favor of the three best teams from that league. It’s not yet panic time this season if you’re there, but you’d really prefer not to be regardless.
As for specific players to watch, there are a lot of talented midfielders in this match who will be spending their next month at the World Cup. Maddison (England), Tielemans (Belgium) for Leicester, Rice (England), Paqueta (Brazil) for West Ham are all good ones to keep an eye on.
Some other particularly narrative-rich players to note.
Kurt Zouma - West Ham defender, you will likely hear an unusual amount of booing when he touches the ball, especially from the away fans. This is because there was video last year of him being cruel to a cat.
Jamie Vardy - Leicester striker on the bench is past his prime, but is probably the biggest “from the bottom to the top” success story in recent league history. He went from playing amateur soccer part-time to winning a shock EPL title with Leicester and being an English international. His wife was also recently in the news for ratting things out about Wayne Rooney and *his* wife to the tabloid press. This means that if he does come in off the bench, you might find yourself participating in one of my favorite recent football chants of “Jamie Vardy, your wife is a grass!”