Elo Rating System in CSGO
One might ask, if Elo Rating system is used in 1-Versus-1 game sessions, how can it be implemented in a team-based 5v5 game such as CSGO? The answer is simple, every round (please bear in mind every ROUND, not every game) will be treated like a single game of chess wherein the team with higher Elo Points is expected to win. Each team consists of 5 players which may or may not have the same rank, therefore their total Elo Points will be considered for the purpose of prediction. Consequently, a player with less Elo Points than the rest of the team would lose (give to the enemy team) less points than one with more points in case of a Round Loss and vice versa.

Please bear in mind, that each Rank covers a seemingly wide range of Elo Points. For instance, two people with the same Rank may not have the same amount of Elo Points. A player close to promotion would obviously have more Elo Points than one close to demotion, even though both have the same Skill Group (Rank). A skill group is more like a tag on a certain range of Elo Points.

One other thing worth mentioning is the fact that the Elo Point range considered for deciding a player's Skill Group is NOT relative. What this sentence means is that for example if players with Elo Rating of 1000-1500 are considered MGE, when a player with 1450 Points gains 51 more points, he will advance to DMG but he WILL get demoted back to MGE if he loses the exact same 51 points in the next games. I explained this because another guide claimed that the seemingly slider used for deciding ranks gets "reset" on each promotion and/or demotion which I believe is false. The reason it's rare to derank on a loss immediately after gaining a rank is because it's unlikely to lose enough points to cause it NOT because the points are reset.

In order to shed some more light on this subject, I would provide you the following example, please bear in mind that the numbers and information provided is just for the purpose of this example and may not (and probably aren't) exact:

MG2 = 500-999 Points
MGE = 1000-1499 Points
DMG = 1500-1999 Points
LE = 2000-2499 Points

Team #1 consists of 4 MGEs and 1 DMG with a total points of 6900:
Player A = MGE with 1200p
Player B = MGE with 1350p
Player C = MGE with 1050p
Player D = DMG with 1850p
Player E = MGE with 1450p

Team #2 consists of 3 MGEs and 2 DMG with a total points of 6600:
Player F = DMG with 1600p
Player G = MGE with 1100p
Player H = MGE with 1050p
Player I = DMG with 1650p
Player J = MGE with 1200p

As we can see Team #1 has higher total points than Team #2 even though they have lower ranks. Consequently, Team #1 is expected to win rounds until they lose enough points to have less total points left than Team #2. Team #1 will gain less points on Round Wins than Team #2 because they are expected to win, but if Team #2 turns it around and Win Rounds they will take more points from Team #1 than the other way around. All points won and lost are taken from the oposite team, you don't get points out of thin air. If a player gains points, another most lose.

Even though Team #2 gains more Total Points if the win rounds, the points are NOT evenly distributed among its members. The member with less Elo Points gets a bigger share than one with more. Consequently if Team #2 wins a round and takes for example 100 Points from Team #1. Player H will get more points than Player I because he had less points. Each player will NOT get 20p.

The game does NOT predict if a Team is supposed to win a game or how many rounds a team is supposed to win. Every single round is treated as a chess match. The Team with more points is always expected to win until they lose enough to the opposite team for them to have more points. So a Team with more points always loses more points on Round Loss and gains less points on Round Win than the opposite team.

However, there is another factor taken into consideration which is MVP. MVP is given to a player which has done the most work for their team. Please note that a player with 5 kill can still lose the MVP to a person who defuses or successfully detonated the bomb. The reason for this is because, CSGO is a team-based game, a player can kill the whole enemy Team but still lose the round because he may not have the defuser to defuse the bomb in time.

A player with most point on each team is expected to take the MVP each round until someone else gains more points. If the player with most points gains the MVP, he will receive his predicted share of Elo Points deducted from the enemy team, however if another player receives it, that player will take some of the gained (those added because of the win, NOT his original points) Elo Points from the player with most points. In other words, any play who gains an MVP will get a SIGNIFICANTLY larger share of Elo Points than other players.

MVP does NOT generate Elo Points out of thin air, it only grants a larger share of the won points. If the player with most Elo Points scores the MVP, he will may or may not receive more points than the other players because it all depends on the setup of the team and how much points each player has. But generally speaking, scoring an MVP will have a huge impact on how much points a player receives for a Round Win.