Why should you be interested in TLS? Well, 'normal' application authentication uses tokens (like SAML, JWT, OAuth). Once an attacker obtains such a token (and no additional client authentication is in place), it is more or less free game for the attacker. An important mechanism which prevents the attacker from obtaining the token is TLS (Transport Layer Security). The strength of the provided security depends on the choice of cipher suite. The cipher suite is chosen by negotiation between client and server. The client provides options and the server chooses the one which has its preference.
Disclaimer: my knowledge is not at the level that I can personally exploit the liabilities in different cipher suites. I've used several posts I found online as references. I have used the OWASP TLS Cheat Sheet extensively which provides many references for further investigation should you wish.
