This P is likely the one you expected from the get-go: promotion entails any online or print advertisement, event, or discount your marketing team creates to increase awareness and interest in your product, and, ultimately, lead to more sales. During this stage, you'll likely see methods like public relations campaigns, advertisements, or social media promotions.
Connecting the dots between marketing and sales is hugely important -- according to Aberdeen Group, companies with strong sales and marketing alignment achieve a 20% annual growth rate, compared to a 4% decline in revenue for companies with poor alignment. If you can improve your customer's' journey through the buying cycle by using digital technologies, then it's likely to reflect positively on your business's bottom line.
A common method of assessing a firm's macro-environment is via a PESTLE (Political, Economic, Social, Technological, Legal, Ecological) analysis. Within a PESTLE analysis, a firm would analyze national political issues, culture and climate, key macroeconomic conditions, health and indicators (such as economic growth, inflation, unemployment, etc.), social trends/attitudes, and the nature of technology's impact on its society and the business processes within the society. 
Because digital marketing has so many options and strategies associated with it, you can get creative and experiment with a variety of marketing tactics on a budget. With digital marketing, you can also use tools like analytics dashboards to monitor the success and ROI of your campaigns more than you could with a traditional promotional content -- such as a billboard or print ad. How to Start a Digital Marketing Agency in 2020 [SMMA]
In-game advertising - In-Game advertising is defined as "inclusion of products or brands within a digital game." The game allows brands or products to place ads within their game, either in a subtle manner or in the form of an advertisement banner. There are many factors that exist in whether brands are successful in their advertising of their brand/product, these being: Type of game, technical platform, 3-D and 4-D technology, game genre, congruity of brand and game, prominence of advertising within the game. Individual factors consist of attitudes towards placement advertisements, game involvement, product involvement, flow or entertainment. The attitude towards the advertising also takes into account not only the message shown but also the attitude towards the game. Dependent of how enjoyable the game is will determine how the brand is perceived, meaning if the game isn't very enjoyable the consumer may subconsciously have a negative attitude towards the brand/product being advertised. In terms of Integrated Marketing Communication "integration of advertising in digital games into the general advertising, communication, and marketing strategy of the firm" is an important as it results in a more clarity about the brand/product and creates a larger overall effect. Digital Marketing for Beginners: 7 Strategies That Work