Do you think that that sdlc effects pmlc or vice versa OR do you think how they affect each other is based on the situation?

How SDLC affect PMLC

Protecting data and systems requires integrating security into every stage of development, from the beginning to the end, from the outset of a project. From conception to decommissioning, the System Development Life Cycle (SDLC) is a multi-stage procedure that includes all of the above (SDLC).
In order to help companies plan and implement security throughout the SDLC and providing appropriate degrees of information security depending on risk is described in detail in the new guide released by the organization. 
As part of system development, enterprises might assess the cost of security controls and mitigation measures against the requirement to protect agency information and assets. Processes for risk management identify critical assets and operations, as well as systemic flaws across the entire business. Risks aren't confined to a single system architecture, but are spread throughout a company as a whole.

Step-by-step explanation

The Step by step procedure.

Information system's entire life cycle is referred to as the system development life cycle. Among the many stages involved are: starting, analyzing, designing, implementing, and maintaining the system. 

Numerous SDLC models and methodologies exist; nevertheless, they always adhere to a standard set of predefined processes or phases. Even if you use an SDLC model, you still need to include information security as a component in order to safeguard the data as it moves through the system.